They probably think BDSM is actually how people would like to live IRL and not just a sexual kink. You'll find a lot of this in hentai/doujin and can't distinguish between a fetish/fantasy and how things actually work IRL.
Basicaly their rationale is "I've seen rape slave porn before, therefore slavery is fine right guys? Surely if they're enjoying it this much..."
Well, I do, and so does any reasonable person. Why are you such a freak?
They probably think BDSM is actually how people would like to live IRL and not just a sexual kink. You'll find a lot of this in hentai/doujin and can't distinguish between a fetish/fantasy and how things actually work IRL.
Basicaly their rationale is "I've seen rape slave porn before, therefore slavery is fine right guys? Surely if they're enjoying it this much..."
A reasonable person can distinguish real life and fantasy.