Do what you think is right under the circumstances. Help if you can, without overly risking you becoming victim no.2, which only makes it worse for everyone.
It may be that you don't have a duty to go to that non-buddy diver who's alone and giving the throat-cut signal, and give him your octo, I don't know. What I do know is that if you don't, you're a total ****...
From a moral standpoint you are right. The bummer of it is that we have seen too many reports of someone breaking into a home getting shot and suing the home owner and winning, Things like that forces second thought as to whether one wants to take the chance of exposing them selves to possible later reprocussions. Makes people think twice about diving with instabuddys. Is the reaction logical perhaps,,,,,, is it understandable ,,,yes,, how do you fix it???? well ,,,,,,,,,