Yes I do think sometimes people forget that fiction is, by its very nature, fictional! But as you say, a good writer will put in enough reality to make the fiction believable, and I suppose that, in a way is where the problem lies. Some people will read fiction and take it as fact, some writers will write fiction badly and/or without any concern for the way it might be received, and we end up with a conception problem that can endure for decades, whether it's about women or gays or Red Indians who always go whoop whoop with a hand over their mouths and say kemosabe a lot.