Universities can simply move the money around. As it is, we probably aren't directly funding Women's Studies, but the money universities get for scientific research enables them to spend their own money (and the money they get from patents on what researchers come up with) on things that aren't taxpayer-funded.
If say money comes in (private or government) for nuclear physics research the university takes 50% in overhead. You say “that’s fair the infrastructure that supports the research has to be paid for!”. If it was just that then great! However it isn’t, the money goes into a general “pool” to support administrators & departments (such as “studies” departments”) that never bring in a dime.