education in Québec is heavily subsidized by Québec taxpayers. It's only natural that the Québécois get their money's worth by paying less.

University education is heavily subsidized in all provinces. I'm not sure about the exact tuition fees in each province, but this article suggests they're similar.

Quebec is a net recipient of equalization payments from taxpayers in other provinces, so that argument suggests students from elsewhere deserve a similar level of cheap access.

And foreign students also make up a significant portion of university funding in all provinces. I'm not sure how that would factor into the "we paid for it" argument.

And as far as French goes, if anyone intends on graduating in Québec and staying for work should learn the local language.

I'm not against this. I don't know what it would look like in practice, and it would be weird for anglophone universities, but it seems similar to other language requirements Quebec has.