Most political views for most people are used as a signal of tribal identification, rather than as an actual opinion on what the best policy option would be. See: http://slatestarcodex.com/2014/09/30/i-can-tolerate-anything... (long, but worth it)

The camps are essentially a feature, not a bug - though probably not a good feature. The majority of political posts exist to reinforce that tribal identity, sending up a signal and hoping you get some back.

Actual discussion about alternative policy options and their consequences is a small-time hobby most people don't care to partake in. The adversarial behaviors re: "political discussion" make a lot more sense once you stop lumping both types of posts under that single label.