Stain isn't in the wrong but actually the society of heroes! Stain's dream of becoming a hero was crushed due to it "corruption" where many were becoming heroes because of fame/money! Despite his speech to revive the true essence of heroes, words had no effect so he resorted to killing the "fakes" BUT saved Izuku because he saw him as what a hero should be which proves he's not a villain that kills for fun but a man of extreme dedication of his beliefs which makes him a likeable character!
Okay, so since posting that Stain makes me a bit uncomfortable, I’ve done a bit of research. I went to some chatrooms, reddit threads, and read posts about Stain and the appeal of his character. And you are saying some of the same things …
And it’s weird because I feel myself lowkey sympathizing with him.
I still think Stain is a creepy and terrifying mofo … but I kinda get it now.