The underlying problem that no one is talking about is the fact that Social Security is broke. Bush tried to fix it and was shut down. Now this country has to have a steady stream of immigrants to float the Ponzi schem because we have aborted almost 40 million babies since Roe v. Wade.
I will gladly trade my future Social Security benefits (if there will be any anyway) for a secure border/visa enforcement. The problem with justifying 20 Million newly-minted Americans (and their families) is that soon, they will also be demanding benefits from a system in which they have not invested.
You are exactly right that Social Security is a Ponzi scheme. But, you should also know that, true to the scheme, adding more numbers doesn't make the system stable. What happens if one adds, say, 15 Million immediate dependents? The entire system will collapse.
It cannot be saved by simply adding people who will, in turn, demand the system pays. It can only be made worse.