I'm not really worried about rare luxuries. You're talking about a ubiquitous foodstuff the world over, and we treat it like it's no smarter than a clam. It's variously treated as bycatch to suffer and die in nets, trapped as 'pets' or exhibits (and I think long-term confinement has to be hell for intelligent beings), and eaten the good old fashioned way, by sticking them in a pot.

Focusing on a particular way of killing them that strikes humans as gruesome doesn't interest me as much as the global treatment of them.

I actually I don't think eating a live octopus is done (at least a fully grown one) since the suction force of its cups(?) continues quite some time after it's death and can be quite dangerous if it sticks to your throat.

Eating live shrimp is a thing though.

This is a practice with sushi and certain fish, I don't know if it occurs with octopus though. I say this merely to confirm a fact, I am qualifying no judgement here.

If so, that's seriously fucked up subcultural brainwashing.