How about you first do away with welfare, food stamps, social programs, etc, THEN we will look into your libertarian open borders.
As the army used to say, when a libertarian says something like you just did.
“Put open borders in one hand, and ending welfare and social programs in the other hand, and see which one fills quicker.”
Problem is you do not get to decide. You are the minority.
In our system elections have consequences.