Not terribly surprising. But looks like the system manages to handle them pretty well - the paper shows that the probability of getting blocked is up to ~80% after 5 personal attacks.

I've never worried too much about that kind of incivility or 'abuse' - I've always been far more worried about the 'abuse' which takes the form of deleting contributions, which, because it can be justified and rules-lawyered and is not as clearcut as 'you suck', the system does not handle well and culturally encourages.