Hale is at first too prideful, and almost excited to hear that there were witches in Salem, and that he was considered the local expert and called in to check things out. He asks leading questions of people, and seems to not understand sarcasm in the moment, taking everything literally. Again, he has already made up his mind that there are witches in Salem, and not much could change that thought. He does, however, realize later that there wasn't strict proof, and that what he did was wrong, which is more then you can say for most of the characters.