US tax dollars dont pay for foreign students, it's mostly their parents or they have a scholarship from their govt or city.The way you’re asking the question makes it seem like you’re pro foreign nationals attending US universities.
I agree with the last 2 paragraphs of your post.
Not my problem and why should US tax dollars support it?
IF exceptional students get US funding because they provide something or some type of development that can not be found locally usually it's related to research.