I look at unrestricted immigration the same way I look at shipwreck survivors. You have a 15-man life raft, with provisions for 15 persons for 60 days, if allotted correctly. So your ship sinks, and you end up with 15 people in the life raft. So far, so good. But! There are 40 more people in the water, swimming around the life raft. What do you do?
If you try to put 40 extra people in a life raft meant for 15, it will sink, and then you'll *ALL* be in the water, and you will all die. If you try to parcel out food for 15 people to 40 people, everybody will get a mouthful a day, and eventually, you will all starve. There are sharks in the water. If you leave 40 people in the drink, they will die. Is it inhumane to refuse them space on the life raft? But if you take them aboard, the raft goes down, and you will all die. So what do you do?
We have a lot of room in the United States. We could probably find space for possibly millions of aliens here, in places that nobody else is occupying. However, like it or not, most of those places are empty for a reason: there's nothing there to support large numbers of people. You can't set up a town of 150,000 immigrants in the center of Nevada and say, "There you: be well, and prosper." There's no water, no food, and no way to produce any. It would have to be supplied for them from other places inside the country, and again, like it or not, we only have so much surplus that we can dole out before it just isn't there any more. If you go so far as to empty the stores and warehouses and water aquifers in the country supplying millions of freeloaders, eventually the system collapses. Then what have you got?
What you have is a situation where *EVERYBODY* goes down the tubes: aliens, citizens, legals and illegals alike. You cannot sustain 55 people on supplies in a life raft meant for 15. The infrastructure gets overwhelmed, and the country collapses. It ceases to exist. That's what happened when uncounted thousands of Germanic barbarians poured into the Roman Empire in the 5th century. Rome, which had stood for 500 years, ceased to exist. In its place, you had approximately 1,000 years of chaos, anarchy, famine, bloodshed, incessant war, and economic and social stagnation.
I'm not heartless. I know these people are suffering bad times in their own countries. I know the bishops want to follow the injunctions of be good to your neighbor. I know the United States is a rich country with a lot of surplus goods and services and money. I know all this. But the simple fact is, the well, even for a country as rich as the United States, is not bottomless. There is absolutely no possible way we can continue to take in unlimited immigrants month after month, year after year. We don't have supplies for them all. And, just like Rome, we have our own problems: our infrastructure is shaky. Our political system is a corrupt mess. Our economy is exquisitely fragile. If we drive those systems to the point of collapse, they will go down in flames, and then nobody has anything: the aliens will be living in circumstances just like the extreme poverty and hardship that they fled their own countries to avoid, and so will our own citizens. How many is too many? When is it time to say enough? Do the bishops and the leftists want to collapse America until it evaporates and ceases to exist, to be replaced with God knows what, perhaps for millennia? Because that's what's going to happen if we don't send these people back where they came from to solve their own problems in their own countries.