But ask yourself, they are making empty suicidal threats to obtain what exactly? They get their way perhaps but it's a very self destructive path, physically and socially. And eventually, you're going to end up listening to yourself.

Well, there's the problem. These are narcissist hedonists who only care about getting their way, and don't care what they give up to get it.

Now there's a more diplomatic way to deal with this if someone makes the threat towards you. You obviously can't just say "lol ok kill yourself" without looking like the asshole. You can flip the victimhood, go quiet, look disturbed, say you've struggled with your own thoughts of suicide and suicide of others you've known, and are too disturbed to interact with that person again. Which is not the emotional response they are fishing for, and makes them look like the asshole unless they actually kill themselves.

That works. Personally, I like the logical "...so, why should I give you your way to keep you from killing yourself exactly?

If I don't, and you kill yourself, then you're dead. You're no longer a going concern. I can do what I want and not have to bother worrying about what you think.

If I don't, and you do not kill yourself, you just played your card forever. You just proved beyond a shadow of a doubt that you're all talk. I never have to worry about you killing yourself again. I can do what I want and know once and for all you're just bluffing and you won't do shit.

Either way, I have no reason to do what you say."