This is on my mind, since I had to temp-ban someone from c/vegan for it in the past week, and another example of it went unmoderated for hours after being reported in another community (though it was eventually dealt with).
It doesn’t matter how much the person you’re responding to deserves it. Odds are, they will not care. But you know who will care? Any comrades who happen to read the thread and who struggle with suicidal ideation and/or self harm. You could ruin their day. You could be the push that sends them over the edge. Even in the unlikely event that you cause grief to the person you’re responding to, no amount of collateral damage is worth it.
Don’t make suicide bait posts or comments. Don’t upvote suicide bait posts or comments. Report and denounce them wherever they show up.