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.
That's because it isn't just about ideas, it's about power. Politics and government now are not about coming to consensus solutions that everyone, or at least everyone but a small minority who just wants to game the system, can live with. Politics and government now are about imposing on everyone whichever set of ideas gets a slim 51% majority. That isn't the way it was supposed to work.
I personally would like to see a Constitutional amendment that would require a 2/3 majority in both houses of Congress to pass any legislation, and a 3/4 majority required to override a Presidential veto. That would at least require some amount of bipartisan consensus, and therefore some amount of actually somewhat reasonable debate instead of just shouting back and forth, before a public policy was imposed on everyone.