Even if you scope it out to "everyone that's not a citizen or has the equivalent of a green card," is that so evil? If a country accepts immigrants they should be able to send them back at will unless they become citizens. That shouldn't be controversial. You can argue if it's a good or bad policy, of course, but it's not ethically wrong to do so. Yes, they'll be in more danger and have worse lives when they go back to wherever they came from, but again - a country should exist to serve its citizens, not the entire world. It's not sustainable.