That's some serious pom-pom action you just did. There are times when bad faith communication is just a waste of everyone's time. It's great to think that by having a conversation positive results will occur. However, that's not always going to happen. Since I'm not part of a diplomatic entourage where the mere act of continuing to talk past each other is seen as a positive, that same behavior does not tend to benefit normal people. At times, I have chosen to just end/walk away from a conversation just to avoid the energy and inevitable frustration. Maybe it's cynicism, but as you've said, I can't control the outcome but I can control it as far as me continuing to be a part of it.
You're right that my pom-pom action was serious, but it sounds like you're imaging a different kind of dilemma than I was. You're referring to walking away from an unproductive conversation, while I was responding to a cynical argument for choosing bad faith over good.