Comments sections on news sites.

[VG_Addict]

No matter WHAT site it is, the people in the comments section ALWAYS find a way to turn a tragic event, such as a hurricane or a school shooting, into a debate over global warming or gun control, respectively, which devolves into name-calling, such as "Repuglican" or "Dumbocrat". Frankly, I find this to disrespectful to the victims and their families. It's ESPECIALLY bad when said tragic event happens in a red state, as they'll say any of the following: "It's God's punishment for being racist/homophobic/stupid/whatever", "Stupid red states, leeching money from the blue states", or, my personal "favorite", "Hahaha, the red states should secede, the US would be better without them". And MAYBE, you'll see a couple of sensible posters talking about how tragic the event is, that they'll be praying for the families of the victims, and that the previous posters are being disrespectful.

[Ace Mercury]

Based on the caricature that I've seen of the US politics, it's like they're sports teams. Loyalties lies not because of the causes they champion, but rather membership in a political party forms a core part of one's identity. For example, people aren't Republican because they're against gun control, but they are against gun control because they're Republican. Cogent political discourse is a rarity because people are so divided into teams rather than interested in causes.