You don't have to prove that people into BDSM are no more likely to be abusive. I believe that. I don't think we actually disagree on anything, we would just emphasize different parts of the response. That was what my comment was about originally. I agree with everything Prudie wrote, I just think she should have emphasized more the LW's responsibility to his/her son.

Eta: I do appreciate you sharing your experience and perspective on this topic. I'm generally much more sympathetic to children than adults, but perhaps I underestimated the pervasiveness and dangerousness of the false equivalence. I wasn't ready to condemn the LW for making the false equivalence based on a single comment, but it seems this is a broader issue than I realized.