If you take a Queer Studies course, you go in with the assumption you are buying into the fluidity of gender and sexuality. To fight it would be akin to taking a science class and arguing about the mystical application of astrology or alchemy to the discipline.
That's a big reason why I put "academia" in quotes. I don't consider such "Studies" what I think a university should be about (for me, Wissenschaften comes closest) because I think they are unfalsifiable and require non-thinking adherence to the fundamental principles. Want to study such stuff within a regular framework of sociology, psychology, or philosophy? Cool. But creating a separate "Study" discipline too often is a sign that you just don't want to argue about the underlying (very rickety, sometimes indefensible) assumptions.