In fact, you are only describing two groups here — Trump supporters, and the reality-based community.

It is the reality-based community who believe in the overwhelming consensus of science on climate change; who believe both the statistics and the evidence of their own senses on income inequality; and who see a US President repeatedly, unapologetically and successfully fomenting violence against Muslims, “the left” and other perceived enemies and fear for their lives and those in their families and communities.

All your examples of “extremists” are simply people wanting to roll back a few of the changes in the last thirty years! No one’s even proposing moving tax rates to anywhere near what they were under FDR or even Eisenhower.

These extremists just want the government to turn the EPA back on again — no one’s talking about bringing the EPA back to 1970s levels of funding when in inflation-adjusted dollars it was nearly three times bigger than it is now, and was run by people who aggressively wanted to clean up America. Today’s wild-eyed radicals just want to get it back to the barely-functioning state it was in during the Obama administration, where it was unable to actually punish gross wrongdoers but at least continued to function.

Nothing the “radicals” want is actually radical by the standards of the rest of the developed world. Almost every developed country officially believes in climate change (though action is still lagging), has highly affordable healthcare, and has much higher top tax rates than America has had since Reagan.

Your perspective has become skewed by the insanity of this time and place. By the standards of the last hundred years of America, and the standards of the rest of the developed world today, people like AOC and Bernie you perceive as radical are in fact the centrists.