While I do think it's really wierd when people ship Hiddlesworth, write self-insert stuff, etc, I personally don't have a problem with people idolizing Loki. Like I know he's a mass murderer, but he's a FICTIONAL mass murderer, and the people he kills aren't actually alive and stuff. Personally I think it's a bit mean to say people who sympathise with him are weird or whatever because after all, he is fictional. However, I do hate people idolizing actual mass murderers. That's just sick.
It's fine to like and sympathize with Loki, but a lot of his defenders are so over the top that they forget the purpose of a villain/antagonist. I personally think fiction has an effect of what people think of reality, which is what influences some people to idolize real murderers.