Brasas: Good points. Thanks for the effort.
Re: "I think there needs to be agreement between the people engaging to drop a point when its dead"
I think it takes only one to stop an argument - no mutual agreement required usually. Stepping aways does not mean you lost the argument, and there's nothing more comic than somone screaming at the air when their adversary is long gone to do something else. Basically sometimes moving on is the way to "win". This is I think the truth behind the expression
Only way to win is not to play.
Then on the forum specifics, that's definitively getting into object level discussion. I have some thoughts on that but will keep them to myself for now.
Another point, on your conclusion about no one being obligated to be nice, and everyone having a breaking point. I think the best way to address that is for your friends to be such that they pull you back, rather than egg you on. Obviously when you go over the line the ones that made you go over the line (intentionaly or not) are the least likely to be able to deescalate you. What can be tragic though, is when people have blind loyalty, and will support their family and friends regardless of actions. My buddy threw the first punch, but instead of holding him and gettign him out of the brawl, I'll jump right in and punch his victim's buddy. Yay to me, I'm such a good friend. Or maybe I'm just reinforcing destructive behaviors and the right thing to do would be more counterintuitive? But I know it's hard to be a true friend, when the person you are helping does not see it as being helpful, rather the opposite. Tragic really.
I have a nice anecdote about a baby bird and a cowturd making that same point. Not sure you'll want to hear such folksy wisdom though. :D
Final comment. More a question really. What you said about net debates being low risk and low reward surprised me a bit. I hope you can ellaborate, because I actually see the net as high reward. Maybe it's because I am old enough to remember the days before you had the world at your fingertips, but I always felt this shit can be magic. I mean, here I am talking to someone from India, after having had a chat with someone from the Netherlands, all people with wonderfully different approaches to life, from whom I can learn something and if not change my mind, at least get to know them / the world's variety better? That's without considering how easy it is to find people with similar interests as me - in GOG for example I know I can discuss old games and DRM free philosophies whenever I want. I think those are all valuable things, and I get them at a very low cost. You see what I mean?
It does take only one person to stop an argument, but it takes acceptance from the other person to acknowledge something they said is wrong and not keep on repeating it. And I think we need mutual agreement between people arguing to drop an invalid point after its dis proven, and I say agreement to say both sides arguing. Like ''I don't keep pushing disproven points and you return the favor''.
That is the thing though. On the internet, everyone is alone, and treated as individual. There are very rarely friends and most people make it a point to stay out of a fight if they can, friend or not. Yeah, attempts at helping are very likely to fail because you make at least someone angry in the end. Try to intervene too many times and you will be seen as someone trying to ego-boost or gain moral superiority. You can do it via PMing your friend, and that can help I guess, but IMO it won't do good 100% of the time because someone who is already angry may get angrier when more people talk to them. Sometimes, some alone times may fix it.
I'm all for folk wisdom, and anyone reading can probably do with some humor as well :D
Yes it certainly has high potential to be rewarding, but I feel most discussions, especially more combative / argumentative ones give at most the satisfaction (?) of shutting up the person you don't agree with for sometime. In my experience, most people just go about usual business of posting opinions and fighting on the internet. It certainly is a good experience to talk to people with other views, but very few people are as enthusiastic about it as the person interested in conversation is likely to be.