I agree with you. I tried to read a few fics for it, tried to see why people like it since I try not to hate any pairings and have shipped sadomasochistic couples before Knives and Legato in Trigun for the win, but they didn't even come across as a somewhat willing s/m couple, or even as the tragic "slave can't leave" thing. They just came across as "powerful man taking out his frustrations on helpless woman" and "ugh, Shera, you're a freaking rocket scientist, you don't need him, he doesn't need you, JUST FUCKING WALK OUT."

/wipes off self