Unfortunately, calling undereducated and uninformed whites profoundly stupid is not going to win any of them to your point of view. Instead, it will seem to them as if they're being picked on by Eastern, overeducated, choose-your-own-gender liberals who think they're smarter than everyone else, and they're flock again to Donald Trump, who is exceedingly stupid and undereducated, but also tricky and cynical.

One strategy MIGHT be to point out to poor whites how the wealthy are exploiting them. For example, it isn't "globalization" that led to loss of American manufacturing, it was the quest for the cheapest labor, which then led to demand for the cheapest products. Most folks, whites and blacks alike, would rather buy more clothes produced in China that cost less than to buy clothing produced in the U.S. that costs more. Racism makes one stupid, but Consumerism is right up there.

I'll let someone else talk about tax unfairness. For the life of me, I can't understand how "regular people" haven't caught on yet.