Sarcasm is an adjusted stress reaction.

I agree with the "find better stuff" because there is no point constantly watching/reading stuff you find politically repellent (that's why I've given up Joss Whedon crap and why I gave up Patricia D Cornwell years ago). But the "you must write fix-it fic" is... yeah, not everyone actually has the time and literary skill to do that. And I'm more than a bit unhappy about the idea you get among some politicised fans and external academic observers of fandom that all the best/most-interesting fanfic must be stuff that didactically critiques the politics of the source work. It just seems a bit joyless and reductive and instrumental.