Why do so many people like Snape?

I realize that he was Valente and that in the end he did the right thing, but I don't understand why he's so popular.

He was very interested in dark magic and was a real death eater for a long time. He held onto his anger at James, Sirius, and Lupin all his life, and he hated Harry for no reason. He was perfectly willing to hand Sirius over to the dementors without even hearing his side of the story first, and he told everyone about Lupin being a werewolf which made him quit teaching at Hogwarts. Snape was really an immature person. When Harry saw his worst memory he refused to teach Harry how to guard his mind even though it was a very important task. Not to mention the fact that he blatantly favored his own students and didn't punish them when they jinxed or else harmed Gryffindors. He terrorized Neville Longbottom and humiliated several other Gryffindors in front of the class just because he could.


Also, why do Snape fãs bash Lily for not forgiving him for calling her a mudblood? It's basically the equivalent of calling a black person the n word, so I don't think that should be forgiven. And Snape fãs hate James even more. I understand that when he was young, James was cruel to Snape, but James grew up to be a good person. When he found out about Lupin being a werewolf, instead of abandoning him like most people would, he, along with Sirius and Peter, became animagi. James was extremely loyal to his friends and was never tempted to cadastrar-se Voldemort. Lily wouldn't have fallen in amor with him if he were a bad guy.