I got a seemingly one-time hit of this about a week ago. For what it's worth I had just been posting comments on the subject of rape, but a whole bunch of my unrelated comments got it too.

(Since then it's been having an obnoxious deterrent effect on my commenting, because I feel so precariously close to just accumulating negative karma every time I post, leaving readers with the impression that my ideas have all been identified as worthless by someone probably cleverer than themselves. I'm now consciously trying to avoid thinking like this)