I think you misapprehend the situation. Based on my experience with suicidality, the "BS" isn't what actually prompts the suicidal thoughts. Rather, it's post-hoc rationalization for the irrational feeling of having no future worth experiencing. In a broader sense, this is something that people do all the time: we experience an emotion, then try to explain it after-the-fact. Our brains are incredibly adept at inventing "reasons" for experiences and sensations that ultimately stem from bizarre defects of biology and other caprices of circumstance. The mythologies associated with sleep paralysis (the hag, incubi/succubi, alien abduction) are perhaps the most vivid examples of this phenomenon.
