Uh, I'm not into that sort of thing, but for those who are, BDSM stuff probably is romantic, or sexy, or whatever. Romance is pretty fucking subjective. And since it is something done between consenting adults, I don't know why you give a fuck. I haven't read "Fifty Shades of Gray", and I doubt I ever will, but from what I've heard if you're getting your ideas about what BDSM is like from there you're not getting a very accurate picture of it. Also, since when is this some kind of major issue for trans women in particular? I bet there are more than a few trans women out there think BDSM sex stuff is pretty hot. And I doubt they give a fuck what you think about them.
ETA: I went to that Tumblr. Lots of pictures of brides. Most of then described as "crossdressers". And lots of weird memes.