There's a line between insults and cruelty, and he distinctly crossed it several times. Intentionally antagonizing someone who clearly isn't at their most stable is dangerous, and he seems to take joy in doing it. It may not be considered 'criminal' behavior, but I'm pretty sure it's a line below just being disliked.
I disagree. I'm not the only one that thinks I was right, either. My amusement level has nothing to do with the situation at all. I would have done the same, regardless.