In all debates there is (and there should be) a certain amount of 'friction' (not saying violence, insults, name-calling or any type of disrespectful way of addressing your 'contestants'). We do know, in that moment, in that chat, that I like Messi and you like CR7, and we would go to war to defend who is best (Messi, of course, hahaha). This, in my understanding , is still constructive not only for you and me who may end up watching futbol for days and have a lot of fun but also, because, this is the way knowledge has been constructed before formalizing it in what we now know as books, journals, papers, magazines, etc.
I think we underestimate these interactions.
Now, my contribution is to allow the debaters block each other if there are being attacked. If moderation starts getting notified of a used being blocked by many others, then something is wrong and s/he should have his/her account removed for good.