Snapedom

Yeah, that "it's more that he exists" line sure gets a lot of gloss in the defense of James. ;-) If he wasn't referring to Severus' half-blood status, he was certainly referring to some other prejudicial factor: class, economic status, appearance, social "coolness"... oh, take your pick. There are so many to choose from when a bully wants to justify his bullying.

Not that James seems to be really "justifying" it. He seems pretty confident that he's just entitled.

And yes, he "befriended" Lupin the werewolf in school.

Which just sort of gave him the advantage of keeping Lupin from blowing the whistle on him, because if Lupin got out of line, suddenly the full moons were no longer merry romps with animal buddies but an agony of solitary suffering in the Shrieking Shack. It could be coincidence, but I can also see James using it as an excuse to do something fun like learn how to be an animagus. And there may have been some genuine stirring of human spirit in there somewhere, but then wouldn't he, as you say, have provided for Lupin instead of letting the guy live in abject poverty?

Anyway, you've raised good points to ponder. Especially the thought that Lily merely jumped from a superficial bigot who, given the right kind of mentoring, was capable of outgrowing it, into someone who was a dyed-in-the-wool bigot.