Not that I disagree that these issues are horrendous, because they are, but is this not simply an example of what OP is talking about? These are issues that you read in a newspaper, which likely has some sort of politically affiliated funding along with most other mainstream news sources.

The fact that these are the headlines we see all over the place is, in my view, exactly how we are being polarized. Republican and democrat individuals all have various personally constructed worldviews: MOST people are in favor of legal abortion, MOST people strongly desire stricter gun laws, MOST people favor legal gay marriage, almost EVERYONE wants better, cheaper healthcare, recognize that climate change needs to be addressed, etc. When we liberals read media marketed to us, the headlines are framed in a way that it's all republican's fault rather than this catastrophically corrupt government making all these decisions.

It's the same for republicans: when they turn on fox, they are led to believe all liberals want to outright kill babies, force their (the republican's) kids to be "indoctrinated" by "communist" "athiest" school teachers who are all somehow transgender and hate free speech, etc. Both sides are being fed absolutely ridiculous claims about this demonized other that wants to destroy their way of life.

Of course extremists exist, but the vast majority of people I know just have certain values over others and have been brought up in a certain way of life. Can we really say we are any different?

Don't we all want relatively the same things? Safety? Happiness? The ability to live without the existential dread that our leaders are selling our futures for a quick buck? The vast majority of Americans feel utterly cheated, and they are absolutely right. So of course the people who have power do everything they can to manipulate us into pointing fingers at each other rather than themselves.