because sometimes people actually do feel that way. sometimes your life feels like it's caving in on you. sometimes people really do feel like they don't want to exist, like they want to just curl up into a ball, and go into that place between life and death. saying "i don't want to exist" isn't saying "i want to go die" - it's saying "i wish that, for the time being, i could go somewhere and not have to feel". i don't think there's anything wrong with that. and if you don't know how it feels to feel this way, then you have no place to judge anyone who does.