if the trolls cross the line, their posts are deleted and they are banned. I just ignore them because they play nice to win freeps over and then they GET REALLY NASTY. That's how they do it. THEN THEY CROSS THE LINE AND GET BANNED. Just ignore the trolls.
I'm with you: do not even respond to the trolls. It's easy to spot insincere posters who are not interested in genuine debate. Once you spot one, deprive him of the attention he seeks by not taking the bait.