Think about being a child with Professor X's abilities. He can get anything he wants, make anyone believe anything he wants, he can know everyone's deepest most shameful secrets. How could a person like that even form a moral framework? From his childhood, he'd have every reason to believe that he was immune to all discipline and that rules simply don't apply to him if he decides they don't, because for him those are true facts! By all rights Professor X ought to be a an exceptionally dangerous egoist and megalomaniac.
Oh, also, if there is any Marvel character who ought to be canonically omnisexual, it ought to be Charles. He doesn't see bodies, he just sees minds. That undersea prawn monster that Namor was making out with ought to be just table stakes for Professor Xavier.