don’t complain about picking up some of the burden to raise them
I don’t think the latter follows from the former. There are going to be plenty of people here in the future even if childless Americans don’t subsidize Americans with children. That’s the great thing about America - we can just let in the best among the many millions of people who want to come here from other countries. Accepting a young adult who is already educated and ready to do productive work seems like a pretty good deal compared to investing money into a child who won’t be productive for twenty years.
(Both the “accept no immigrants” and the “accept all immigrants” sides are wasting such a valuable opportunity!)