How do the women always know? Maybe the children know.I really don't see a problem with a healthy debate. Although some can get heated, I enjoy reading both sides and I get some good information on subjects that I may not understand all that well. Things I did not think of before. Both sides are worthy of consideration and I support folks freedom to state their opinions, even if I don't agree with them.
The thing I find bothersome is when some people feels they are losing the debate, they will result to bullying or personal attacks. That is not free opinion. I'm not sure what system you use to let people know they are being considered for removal but I think "Bullying" should be added to your list of automatic tossing. It is harder to determine, but should definitely be unacceptable.
You may have already considered a flagging system where your first "offense" you send a "yellow flag" stating "That's one". Next is orange, then red, and your out. That gives people an opportunity to adjust behavior. I know you get tons of suggestions, so you probably already considered this one, but makes sense to me.
Also, no matter what we do in life, our wives always seem to find out...