I think @Sherrerd is mostly correct, but not for exactly the reasons mentioned. It’s even simpler. The world is a complicated place, and for many people in the US, especially older, white people (not exclusive to them, but it’s a big part of the current Trumplican base) it isn’t a world they recognize. They expected a future that was like the past, with a certain degree of unthinking deference due to their race and class, where things worked the way they expected.
It wasn’t ever that simple, and it definitely isn’t now. So they are confused, and probably scared, and someone - Trump/Limbaugh/etc - says “Oh, it isn’t complicated, those OTHERS have all worked against you, follow me and we’ll make it all simple and good again.”
That’s the poisonous and brilliant power of the MAGA theme. Make American (a version of American that only existed in black and white TV) Great (if you were part of the class with unspoken advantages) Again (not that it was if you were a recent immigrant, of color, or different in your social or sexual outlook). This is, to borrow a not random metaphor, a return to Eden.
You get all the power of the previously mentioned Good vs. Evil, but back it up with the comforting simplicity of not having to try to understand or take responsibility for any of the issues that we have increasing needs to address.
And for the conservatives on the board that are not Trumplicans, it’s not like the Democratic Party isn’t full of other simplifications. I do love Bernie Bros that say we can do everything all for free (?) by just raising taxes on all corporations/Wall Street/Rich Guys without discussing how that is going to raise costs to everyone down the line (not that we don’t need to reset corporate taxes to pre-2017 levels, but his estimates were wildly optomistic).
Humans love to see ‘the man with the plan’ and probably have since Chief Loves-to-Loaf in most ancient times promised that life would be better if they gave him extra food so he could make all the complicated decisions while everyone else got on with the hunt, and his brother Shaman Smokes-good-Weed promised that everything would be better in the Food and Women filled afterlife if he interceded with you with the spirits that only he could talk too and negotiate with, all for the low low cost of a share of your gathered food.