"YOU". You should have replaced that with an "I". Anyone else is entitled to dive whatever and however they want so stop trying to force your views onto them.
Never put yourself in a situation where you'll have to blindly rely on a 3rd party to get you out of.
If you have to blindly rely on a buddy then id suggest you take a look at your own equipment, configuration and so on.
Leaving aside the inherent contradiction between your first post and the second two, which goes along the lines of "Don't tell anyone what to do, but this is what
you should have done.", there are a couple of other points here.
1. I do not believe the OP was '[putting himself] in a situation where you'll have to blindly rely on a 3rd party" at all. A quick look at his profile shows that he's a PADI AOW diver, ergo trained to dive with a buddy.
There's nothing blind about that; it's the level of his training, and "equipment, configuration and so on" ain't going to change that. Mention more training and I might agree.
2. Returning to the first post, if the buddy in question was my wife, my kids, a friend or even a less experienced diver and the situation perhaps more dangerous than the one described, I'd have no hesitation in trying to stop them if I really thought they were liable to hurt themselves.
People make bad decisions, sometimes you're in a position to see that it's a bad decision, through experience, training or whatever.
I believe you have a responsibility, especially in a life-endangering position, to act accordingly to avoid the consequences of that bad decision.
Would you seriously ignore someone who was a accident waiting to happen (but unaware of the fact) because you feel that you shouldn't "force your views onto them"?
If you are an Instructor, I hope not.