Why is our political polarization getting worse and worse? Evan Sayet, conservative political commentator and comedian has the answer, and it's for the same reason that conservatives are generally pretty happy while leftists tend to be miserable: Capitalists need friends and socialists need enemies. Think about it.
One reason conservatives are so happy and Leftists are so miserable is that capitalists need friends. They need business partners and investors, trading partners and customers so satisfied they come back again and again.
The socialist needs enemies. There must be people who hate him and oppress him. If he's not hated and oppressed then socialism doesn't exist.
If he can't find any such hatred, he's forced to make it up. "Dog whistles" - he knows what you're REALLY saying -- and "micro-aggressions" are all invented nonsense because this "oppression" simply MUST be true or else there's no socialist movement (and no free things.)
Conservatives do their part in our polarized political climate. Every Republican president since Eisenhower is accused of racism by Democrats. In the past Republicans would seek understanding, explaining that [insert conservative policy prescription here] is not racist, it's designed to help everybody. Then they would meet the Democrats half way by compromising the policy's effectiveness away. Nowadays Republicans are more likely to push back.
Maybe it's something they seem finally to be picking up from Trump. He never lets a smear go unchallenged, recognizing that Democrat charges of racism are not about misunderstandings. They are insufferable, intolerable insults. The bad news for Democrats is in their success at creating enemies. Their insults are alienating an ever growing block of the electorate.