I agree, they're not selfish, they just don't see a way out of their misery.
Maybe they have a chemical imbalance in their brains, depression, a misperception of reality pointing at all that is wrong or they just don't see a way out of the reality they hate so much. Plenty of talk about rape victims in college who are bullied because their rapist is a popular guy and they kill themselves. I've read men are more likely to kill themselves because of money while women have a tendency to do it because of love.
I'm sure not even Bourdain knew what led him to end his life. God knows why Arpad Miklos did the same: lack of future, feeling like an object, end of his career, etc.