Sounds like you should have just ignored them instead of stating something completely obvious. Advice is one thing but most people get annoyed when they get called out for something blatantly dumb they did. If it was a mistake they probably just got defensive. If not, trolls will troll, you just fed them again better to just ignore it. Getting snippy and calling names like childish is just as much harassment, so unfortunately you don't have a leg to stand on. Best bet is roll with friends if you can and boot people who are being jerks.