Considering that Huckabee isn't a conservative and those three are, how should they have treated him? They probably treat Hillary Clinton about the same.
Actually, come to think of it, I've heard Hannity say some very nice things about Huckabee.
“The treatment Fox News and “conservative” celebrities like Ann Coulter, Laura Ingraham & Sean Hannity have given to Mike Huckabee is deserving of shame and infamy.”
Any one of those three people you mention are more a conservative than Mike Huckabee has ever been or ever will be.