Sharing opinions on what is good or evil, truth or baloney, isn't a bad thing. This is what is done in academia and among scientists even. Debate hones the mind to discover things that don't work. But when folks start slinging mud, that's the time for the bouncers to step in.
Also, moderators must not be allowed to participate in discussions. It's not fair to let referee fight in the ring and call foul at the same time. If a moderator wants to fight, ditch his role, put on gloves and be prepared to get floored by a haymaker that can rip his head off his neck.