Reading about something is not "literally saying you're okay" with whatever behavior is depicted in the fiction. (That's not really what the original poster was saying, I know, which is why I'm not using an auto-quote.)
People have been reading with pleasure about things they would find abhorrent in real life and other people have been giving them shit about it literally before widespread literacy even existed (see Plato, The Republic).
johnb suggests that there's something necessary and cathartic for some people about coming into a forum and decrying fictional behavior as if it's real.
I don't quite get it myself, but as every Itou Hachi thread demonstrates, it happens so often it must be true.