Here's what politics was like ~30 years ago (in the US): your representative was rewarded primarily on the basis of local issues and economics. For us it was 'can they keep the local Navy base open' which provided most jobs. You can see the remnants of this pork-barrel politics in the Obamacare deal, with various deals to bring over a few senators.

The US had tons of diversity. But it got expression in local culture, and you didn't think as deeply about your identity at a national level. The national stuff felt more distant. It was exceedingly rare families to travel outside one or two state radius.

NOW, perhaps due to the Internet, maybe other factors, everything far away feels 'closer'. It's like we're suddenly crammed together at the same party, sharing more space with people that we would have culturally been more distant from in the past, creating tons of issues. Most issues have become nationalized. The lack of local media compared to social media, the lack of attachment to a community (people move more), and other factors probably are at play here.

So everyone projects values in the past they would have put into local communities onto the shared, national space. Of course if I project my educated, metropolitan PoV and you project your rural working class PoV, things will clash and we will have fundamental disagreements about everything, including facts and core values.