Billy definitely gets too much sympathy considering all the things he did before he was flayed. (The things flayed Billy did weren't up to him) But I agree with @Paxte 's point that many other characters in the show were just as, if not more, traumatized as Billy and did not resort to the things Billy did before his flaying. Billy being a traumatized teenager is an explanation for his behavior, not an excuse.
That being said I don't think Billy deserved to be flayed/die because at the end of the day he was just a teenager and still had the opportunity later in his life to make better decisions and make some sort of mends for the wrongs he did.
But as for the Billy we knew in Season 2 and from context of his character before he was seen in the show he was a horrible bully/racist who had the ability to be better than his father was to him, yet chose not to.
