A lot of villains become anti-heroes and then just heroes because the audience loved them so much the writers changed them to work as main characters with their own stories
Magneto is different. He became an anti-hero because the farther in the future we are the harder it is to criticize his points
I mean... Magneto has given humanity A LOT of second chances. But, to punish everyone when most people have very little say over who their leaders are is just more fascism.
Professor X should use Cerebro to sus out the genocidal humans and make them live on Genosha. But I guess he IS a centrist.