I find it interesting that of the early attempts at addressing things like homophobia and transphobia, by including an LGBT guest character and having the poorly-reacting main character learn a lesson, so many of them seem to have been comedies.

I might posit that comedies allow for defusing audience (and producer/studio) tension with lots of jokes, and comedies created these sort of parallel fundamentally-comic universes that might not make homophobic/transphobic executives and viewers panic quite so hard? (I mean not just in the sense of the jokes, but also in the sense that a parallel/comic universe isn't quite as Real as a drama, which helps panicky people feel distance from the thing that panics them?)

Also, of course, comedies allowed for the have-cake/eat-cake thing, where you can be mainly pushing the progressive/inclusive message, but also have homophobic and transphobic jokes intended to be laughed at. Archie-Bunker-style.