Diamond is an independent, though, not a Libertarian.
For whatever reason, he's running as and Independent but he has always run as a Libertarian before.
So Diamond attracts the vote of libertarians and also conservatives who don't want to vote for some football celebrity who doesn't know what the hell he's doing.
I wouldn't jump to the conclusion that he doesn't know what he's doing just yet. Rendell is supposed to be such a smart guy but spends so much of his time during football season as a commentator. I'd rather have the football celebrity concentrating on being Governor than the Governor concentrating on on a game.