Skinny people and /fit/ people have, on average, more willpower than fatties. When skinny and /fit/ people decide that their lives aren't worth it anymore, they end it. Like that. They have the mental strength to go through with their ideas, to do what they want.
Fat people are disgusting, useless beings. They may live for their whole lives wishing they were dead. They don't go through with suicide, because they're afraid, and lack willpower. They have never done anything with their lives, and never will. They realize that their lives aren't worth living, but don't have the strength to just say enough is enough and end.
Fat people are subhuman scum.