Because they are ignorant and think just because he worked in oil that somehow makes him a bad person.
If you watched the debate last Thursday I don't see how you can be against the guy. He gave honest, straight-forward answers. He doesn't sound like a politician when he talks, he sounds like a practical business man that knows what needs to be done to help turn things around.
I'm as conservative as they come, but these ultra right-wingers want someone in there who is going to say "absolutely no government involved whatsoever!" Sorry, but we've gone too far down the path to drastically change things now. Haslam knows this and is going to do a good job because he's a smart person and IMO knows what needs to be done.