I think it's really hard, if not impossible, to make that determination, and that's the moral hazard. There are also people who believe that any desire to commit suicide is a mental health issue that can and should be fixed.
I think it's reasonable to always err on the side of caution, since obviously we can't (yet) reverse death, so there's no going back in the case where the causes of the suicidal feelings can actually be fixed.
But I also believe in self-determination: if you really are determined to end your life -- for any reason -- you should be allowed to do so.
So I guess I'm personally somewhere in the middle: try to stop suicide attempts, but if, after getting help, the person still wants to end their life, maybe you should just respect their wishes and let them go, as hard as doing so may be.
Explain to me how you differentiate outside of the relatively clear cases, such as physician-assisted suicide?
Using "retarded" as a pejorative--we're already not in a good place. But I'd like to hear your reasoning, if it exists.