Are you quite serious? Try reading the threadmarks for actual explanations of how their transgressions aren't mere "writing of racist or sexist or homophobic characters," but racist and sexist and homophobic writing.
Musing on whether it's acceptable to write in-universe misdeeds is a silly strawman. There's a reason A Song of Ice and Fire has such a progressive following despite taking place in a misogynistic feudal patriarchy — because Martin is a progressive writer despite having characters who are quite the opposite.
People are quite capable of separating the writer from their fiction, but sometimes the writing choices inform on the character of the writer.
