I have sat down with beautiful, young, wealthy, high-achieving people with families who have attempted suicide and asked them what they have to live for, and they literally cannot think of a thing. Sometimes people truly believe their loved ones will be better off without them, sometimes they completely but honestly downplay the effect it will have on loved ones, sometimes they recognize it would have been awful for them but at the point they were at before committing suicide they just literally didn’t/ couldn’t think of it.
Suicide is not an “appropriate” response to many situations (terminal illnesses and the like excluded), but expecting an appropriate response from someone whose disease renders them incapable of thinking rationally about many things, including their own death, is itself not rational. Yes, we need to try to prevent depression from occurring, help depressed people not get to that point, and we need to intervene if at all possible with people who are suicidal. But to me “desperate” is more accurate than “selfish”.
I would feel furious and completely betrayed if someone I loved killed themselves, and I’m sorry you’ve had to go through that multiple times. I disagree with your viewpoint, but I do see where you’re coming from.