I have kind of sneaking suspicion that if we really knew all the details of Heinlein's personal life (which he very carefully kept away from the public while he was alive) we might have reason for horror there too, so yeah, I'm hesitant to condemn without reading any at all? On the other hand idk there's probably a reason I have a whole stack and never felt inspired to dig in even before I knew that stuff.

Zelazny is probably an auto-M for me, although I actually like some of his others more than Amber (Lord of Light, Doorways in the Sand, My Immortal....) But then again some of his stand-alones are not good at all, so that could be one of them.