Also, I believe that we're constantly hearing so many voices trying to convince us one way or another, that our own discussions on those topics end up being attempts to convince others. That would explain "safe spaces" to some degree -- people don't want the pressure of having someone else try to convince them of something they don't agree with.
Some of it just the two-party system. The points don't matter, just which side of the line each person is on. I wonder if more parties would help depolarize the situation. I'm really not sure.
[1] but then again, we had a mid-nineteenth century religiously-motivated civil war and it only killed a few hundred people. So maybe we support a plurality of parties because we're less polarisable, and not the other way around?
(rather than having a fabric of society, prone to ripping, having a dense irregular felt of society, of tocquevillean overlapping voluntary associations, FTW?)