Have you ever noticed how many people show two noticeably different personalities? There is a kind and friendly disposition -- it's typically reserved for those on the "approved" list. Then there is the other side. I think one reason people avoid discussing politics and religion in public is the number of people who have their Mr. Hyde button pushed by those topics, or by being in the presence of those who disagree with them on those topics.
I was recently around someone whose Mr. Hyde button had been pushed -- though I suspect another person around was trying very hard to push that button. (I saw this same thing happen with more than one set of people today.) I also suspect, if I'm reading cues right, that at least one of our Mr. Hydes very much enjoyed having his button pushed. Maybe some people suppose venting releases the dark side rather than simply exercising it. When someone pushes our buttons, I think that our inner Mr. Hyde is more like an athlete who has just had some strenuous exercise: he may rest well for awhile with a satisfied glow, but he becomes stronger and more accustomed to the exercise with each opportunity we give.
I wonder if people appreciate the extent to which hatred is corrosive and incendiary, the extent to which "provocative" conversations are throwing verbal Molotov cocktails. At what level of heat does conversation stop working? Once someone's Mr. Hyde button has been pushed on a topic, am I just imagining it, or does it take ever less provocation to switch over to Mr. Hyde the next time? Is there a threshold at which someone can't discuss a topic rationally again without some sort of intervention or healing?
The part that concerns me is this: how close are we, as a society, to the threshold at which rational discussion breaks down except among people who are already like-minded? What would that mean for democracy?