Is extreme (very violent) consensual sadomasochism morally wrong? If so, should
The old principle of liberty that one can do what one likes so long as it doesn't harm others (famously formulated by John Stuart Mill) is challeneged by this sort of issue. What if someone consents to being harmed or even asks to be harmed? Can one consent to be another's slave? My view is that liberty has been found to be such a good thing that it should be maximized. But it does have limits. Sometimes those limits have to do with advancing collective, social, or political goods, like education and equality. Sometimes they involve protecting people from themselves. Why should people be protected from themselves? Because our actions towards ourselves as well as towards others are not matters of simple will disconnected from the structures of character, coercive power relationships, psychological manipulation and pathology, deceit, and plain old stupidity.
On this score, I vote for maximal sexual liberty. And so I support undermining compulsory heterosexuality, compulsory binary relationships, and fixed sexual and gender identities. I find limited sado-masochism permissible. But experience and history suggest that extremely violent relationships are likely pathological, abusive, exploitive, sexist, and deceptive. For these reasons, sado-masochistic practices that lead to serious injury (broken bones, loss of life, hospitalization, trauma) should be prohibited by law. Games of Russian roulette and "consensual" slavery are impermissible for similar reasons.