Caring about the overall number of crimes rather than the rate isn't too unreasonable, but I think it comes from a reductionist perspective where the immigrant isn't thought to bring anything else to the table or is considered negative in other ways. It also could be justified on the grounds that we care when immigrants victimize natives, but don't care when immigrants victimize immigrants or natives victimize immigrants--but you mostly addressed that point.
I could imagine a policy to introduce deer into a city, but people might express concern about car accidents. I could argue that this specific type of deer is less likely to cause car accidents, but they shouldn't care--we don't care about the rate. We care about the accidents. But if the deer actually benefit the ecosystem and are a positive contribution, and we already like the idea of a native deer population, then the rate should matter more.
I think the point about the rate does introduce a problem. If we are thinking in such a reductionistic way, then it undermines the case for native fertility. We could reduce crime if fertility is 0, but I want people having children because they make their parents happy, they have lives worth living, and they contribute to society when they grow up. Similarly, immigrants have positive benefits and shouldn't be viewed in such a reductionistic way.
If I am a native resident of a certain country, what I care about is my risk of being a crime victim. Crudely, that risk is given by the crime rate of a country. Introducing a low (but non-zero) crime population to your country should at first blush bring the average crime rate down, not up.
If you have a population population of 100 pickpockets in your city of 1 million, but you then add 500k residents, you reduce your risk of being pick-pocketed by 33% because the new residents are "absorbing" some of the pick-pocketing. Now if 30 if the new residents become pickpockets themselves your risk increases again, but it is still 13% lower as it was prior to the migrant influx. I think your deer example is dis-analogous because it neglects this absorption effect.
This analysis could still fail because maybe criminals only target non-migrants. But Illegal immigrants are more often the victim of crime because they carry more cash and don't have access to legal recourse.
Finally, one could object that an increase in population could induce criminality in the native population. The population density of a country doesn't really predict crime rates though. Perhaps the only thing you could point to is that bigger cities have a higher crime rate than small towns. But those benefits are really dwarfed by the advantages of the agglomeration effect. In any case, if you don't like the tradeoff you can still move to another smaller town. There are plenty of those around.
Imagine two countries: Syldavia and Borduria. In Syldavia, if your home lacks private security, it has a 1 in 3000 chance of being burgled; in Borduria it has a 1 in 3 chance. In Syldavia, if you wander the streets alone at night, you have a 1 in 3000 chance of being mugged; in Borduria you have a 1 in 3 chance. These statistics make behaviour very different in the two countries. In Syldavia, almost no one has private security for their home, and almost no one travels at night exclusively by registered taxi. In Borduria almost everyone does both. As a consequence, the actual crime rate is about the same in the two countries. In some years, Syldavia even has a higher crime rate than Borduria, because some Syldavians can become too blasé about how wonderfully crime-free their society is.
What’s the point of my example? First, even if the two countries have near-identical crime statistics, it’s obvious Borduria is the more fearful place to live. We’ve all heard the refrain that the fear of crime is worse than the likelihood of experiencing it. But this misses the point that, where people have a reasonable fear of crime, they modulate their behaviour to minimise risk. Syldavians learn to behave like Syldavians, and Bordurians like Bordurians. If a Bordurian behaves like a Syldavian in Borduria, he’ll likely be burgled and mugged. After that learning experience, he’ll change.
The restrictionist logic seems to be "rates, schmates, every crime by someone who wasn't supposed to be here is one more crime that didn't have to happen." Fair enough, but by that same logic, every crime victim who also wasn't supposed to be here, took a proverbial or literal bullet for some other potential victim, who was. Or, as is often the case, when neither the perp nor the victim were supposed to be here, that same crime was going to happen anyway. It just wouldn't have happened here.
Once you count all crimes by people who weren't supposed to be here (regardless of victim), and deduct all the crimes against people who weren't supposed to be here (regardless of perp), I suspect that the raw total of crimes against people who *were* supposed to be here, goes down.
What kind of native-born Americans live in Detroit?
Caring about the overall number of crimes rather than the rate isn't too unreasonable, but I think it comes from a reductionist perspective where the immigrant isn't thought to bring anything else to the table or is considered negative in other ways. It also could be justified on the grounds that we care when immigrants victimize natives, but don't care when immigrants victimize immigrants or natives victimize immigrants--but you mostly addressed that point.
I could imagine a policy to introduce deer into a city, but people might express concern about car accidents. I could argue that this specific type of deer is less likely to cause car accidents, but they shouldn't care--we don't care about the rate. We care about the accidents. But if the deer actually benefit the ecosystem and are a positive contribution, and we already like the idea of a native deer population, then the rate should matter more.
I think the point about the rate does introduce a problem. If we are thinking in such a reductionistic way, then it undermines the case for native fertility. We could reduce crime if fertility is 0, but I want people having children because they make their parents happy, they have lives worth living, and they contribute to society when they grow up. Similarly, immigrants have positive benefits and shouldn't be viewed in such a reductionistic way.
If I am a native resident of a certain country, what I care about is my risk of being a crime victim. Crudely, that risk is given by the crime rate of a country. Introducing a low (but non-zero) crime population to your country should at first blush bring the average crime rate down, not up.
If you have a population population of 100 pickpockets in your city of 1 million, but you then add 500k residents, you reduce your risk of being pick-pocketed by 33% because the new residents are "absorbing" some of the pick-pocketing. Now if 30 if the new residents become pickpockets themselves your risk increases again, but it is still 13% lower as it was prior to the migrant influx. I think your deer example is dis-analogous because it neglects this absorption effect.
This analysis could still fail because maybe criminals only target non-migrants. But Illegal immigrants are more often the victim of crime because they carry more cash and don't have access to legal recourse.
Finally, one could object that an increase in population could induce criminality in the native population. The population density of a country doesn't really predict crime rates though. Perhaps the only thing you could point to is that bigger cities have a higher crime rate than small towns. But those benefits are really dwarfed by the advantages of the agglomeration effect. In any case, if you don't like the tradeoff you can still move to another smaller town. There are plenty of those around.
Imagine two countries: Syldavia and Borduria. In Syldavia, if your home lacks private security, it has a 1 in 3000 chance of being burgled; in Borduria it has a 1 in 3 chance. In Syldavia, if you wander the streets alone at night, you have a 1 in 3000 chance of being mugged; in Borduria you have a 1 in 3 chance. These statistics make behaviour very different in the two countries. In Syldavia, almost no one has private security for their home, and almost no one travels at night exclusively by registered taxi. In Borduria almost everyone does both. As a consequence, the actual crime rate is about the same in the two countries. In some years, Syldavia even has a higher crime rate than Borduria, because some Syldavians can become too blasé about how wonderfully crime-free their society is.
What’s the point of my example? First, even if the two countries have near-identical crime statistics, it’s obvious Borduria is the more fearful place to live. We’ve all heard the refrain that the fear of crime is worse than the likelihood of experiencing it. But this misses the point that, where people have a reasonable fear of crime, they modulate their behaviour to minimise risk. Syldavians learn to behave like Syldavians, and Bordurians like Bordurians. If a Bordurian behaves like a Syldavian in Borduria, he’ll likely be burgled and mugged. After that learning experience, he’ll change.
We're comparing two populations located in the same country.
The restrictionist logic seems to be "rates, schmates, every crime by someone who wasn't supposed to be here is one more crime that didn't have to happen." Fair enough, but by that same logic, every crime victim who also wasn't supposed to be here, took a proverbial or literal bullet for some other potential victim, who was. Or, as is often the case, when neither the perp nor the victim were supposed to be here, that same crime was going to happen anyway. It just wouldn't have happened here.
Once you count all crimes by people who weren't supposed to be here (regardless of victim), and deduct all the crimes against people who weren't supposed to be here (regardless of perp), I suspect that the raw total of crimes against people who *were* supposed to be here, goes down.