The reason we should be paying for foster kids' college is because the state is their parent, so it's our responsibility. In a country that wasn't shit, regular people would be jealous of how kids who were wards of the state lived, and how well-raised they were. There's no clearer illustration of our values than the fact that children who, through no fault of their own, have become the responsibility of the state are treated like unwanted trash. The idea that a society like that could figure out how to ethically treat prisoners or immigrants is laughable.
Absolutely. As my mother used to say, parents should (at a minimum) pay for education and therapy (not to mention housing with electricity and indoor plumbing, food, clothes, etc.). Since the government of California is the legal guardian of these children, it's really the least they can do.