It only seems insane to someone completely averse to nihilistic thought processes. If you believe that everything in this life and universe are effectively mean

It only seems insane to someone completely averse to nihilistic thought processes. If you believe that everything in this life and universe are effectively meaningless then ending your own microscopic existence is basically irrelevant. My understanding of his comment was that he was trying to convey the above, not necessarily argue that feeling depressed one day (or year!) makes killing yourself a fantastic idea. See: "Of course, people might also make emotion-based decisions to kill themselves, which might be a symptom of their depression or whatever, but that doesn't mean that all suicide must be a mistake."