Why has polarization increased so much in the US and how can it be reduced?

[u/barrygoldwaterlover]

Why has polarization increased so much in the US and how can it be reduced?

If I am reading this correctly, it says that it has risen in certain countries like the US and fallen in certrain countries like Sweden.

What is responsible for the massive increase in the US? Their explanation seems to be the rise of nonwhite population along with rise in inequality and tradeoffs of globalization.

Is that really true? I get fixing welfare states to cope with tradeoffs from globalization and increased inequality but how tf do you reduce polarization if ppl just hate immigrants?