Veronaz, you're being argumentative and rude. Knock it off.
Diane, just because someone throws down a gauntlet, doesn't mean you have to pick it up.
As for how mods kniw which threads are problematic, reporting a post or thread puts it on the radar. Once it's on the radar, we can look at various stats, like how much traffic it's getting, which will tell us where the troll bait is. Also, certain topics are hot buttons, as we've all noticed.