PhD students are paid as well, at least in research departments.

Postdocs/PhDs theoretically are supposed to be paid to advance scientific knowledge.

Physicians are not advancing scientific knowledge.

Also a co-op during a CS degree isnt paid with taxes.

I think I understand where you're coming from, but even ignoring resident salaries the majority of other healthcare spending is already government-funded, and in my ideal world all of it would be, so it's hard for me to be upset about this.

I don't understand your point about scientific knowledge, in my mind keeping people alive is at least equally as important as advancing scientific knowledge.

> Physicians are not advancing scientific knowledge.

Yes, but they are providing a similarly valuable service. And, in fact, almost all medical practice contributes to the development of knowledge as well. Lot's of physicians (even residents) write papers.