The money used to support it comes from our taxes.
It is a design choice - a Republican one - that we make legal immigration so difficult and time consuming that immigrants can’t quickly get through the legal process and then pay for the process with their taxes. This argument lets the GOP design their own problem and then complain it isn’t solved.
Unmanaged immigration is not good.
Straw man. No-one is arguing for unmanaged immigration; they are arguing for more immigration that is managed.
Immigration laws exist for a reason.
Yes, but you are talking like you don’t know what that reason is, so I’ll tell you. Per the Constitution, the number of House members a state gets depends on its human population, regardless of status. That means immigrants of all sorts, even illegal ones, count for it while standing in the state. The GOP and DNC both assume that districts with high immigrant populations will vote for the DNC, so the DNC always fights for making immigration easier and the GOP always gights for making it easier. Immigration laws are about preserving political power, not protecting your tax dollars.
I should know, I went through the entire US immigration process legally myself and even sponsored an immigrant while providing support for them.
Then how is it you seem to labor under the misapprehension that legal immigration is implemented in a practically functional way? Its backlog is quite infamous.