This is a fascinating and enlightening discussion of a movie I never understood, and never tried very hard to understand. To me, it just seemed like a campy musical sendup of horror movie tropes with the twist of transgressive sexuality. To take it seriously was not an option I ever seriously considered.
That said, what you say seems to make sense, and I applaud you for considering first the positive impact of the movie before dissecting its deeper flaws and failures.
The question remains, though, why so many of the folks whose representation was so toxic in the show, did and still do love it so well.