Byron York put it best:
Huntsman's problem was that, whatever his position on some key issues, he sent out political and cultural signals that screamed NPR, and not Fox News, that screamed liberal, and not conservative. Even though conservatives agreed with Huntsman on many things, they instinctively sensed he wasn't their guy.
And what does that mean? It means he thought gay people's relationships deserved recognition if not civil marriage; that climate change was real, with the question being what to do about it, if anything; that evolution was not something still up for serious debate. These are culturally and religiously anathema to the current GOP, for purely tribal reasons. Not because these things aren't true, but purely because Democrats or liberals and the vast majority of educated human beings take them for granted.
What you see in the rejection of Huntsman is the Republican body rejecting a sanity transplant. Based on unreason and hatred of the other half of America. It's irrational and degenerate. But it's what they have, sadly, become.
But that doesn't excuse Huntsman's dreadful campaign. It was so tone-deaf from the get-go, you almost missed Romney. I wish the dude well; he was, in the end, the man the Dish endorsed, after the Ron Paul newsletters made him simply too tainted. But I fear he did not do much to advance his future by this sad performance. The Republicans await their Cameron. But for now, they are so consumed with cultural loathing, they cannot see anything that clearly.