He's not confusing sex and violence he is having a difficult time differentiating between coercive violent acts perpetrated sexually and consensual sexual acts that appear violent. The point still stands. Many people make this same mistake. If BDSM practitioners want their practices accepted by those in the mainstream they will have to deal with the fact that many people hold this same erroneous belief. Telling everyone how ridiculous the idea is does nothing to dissuade them of this opinion.
Chuck is correct in noting that many people already engage in what they label kinky sex. Most of them however seem to think they are further outside mainstream behaviour than they are. That may be part of the appeal, imagining they are much more transgressive than they actually are.
I also haven't seen any of the alleged hostility towards BDSM that some complained of. I don't recall any from the past either but my memory is far from perfect.
John Thornton