Calling it Left vs Right culture is kinda over simplifying it but kinda. The problem is that a lot of regions have shifted in their beliefs and even further separated since the civil war, just cause I and a Utah Mormon live vaguely similar day to day lives doesn't mean we are culturally compatible.

This is closer to the Yugoslav troubles before its initial break down in the 90s, a bunch of cultures who while broadly similar on a surface level have friction with one another regardless due to deeper issues. It just happens to be manifesting on a political level since most Americans will happily suppress their own regional identity in favor of the American imperial Identity.