This part of thread did start with concerns expressed that many leftists don't understand or that Jim Straub finds he has to constantly explain it all to leftists. You might want to consider that it is not immediately evident how BSDM is distinct from some other things, since there is some superficial similarity. Rather than be amazed that some people thinking about it for the first time make comparisons, you should really be able to understand their confusion more readily rather than acting as if it makes no sense for anybody to wonder about it.
And there is a big problem of male violence against women that many leftists struggle with and are sincerely concerned to do something about.
Charles