The "red vs blue team" thing is a US thing, and it is created by the structure of our political (and, especially, our electoral) system. First-past-the-post voting, combined with widely open primaries, result in both parties gradually drifting apart over time, and dragging their constituencies with them. That this erupts into verbal (and, occasionally, non-verbal) violence is not surprising, but what you see on social media is the symptom, not the cause.