I think you give many of these people too much credit to think that intellectually. I think most of it is just good old fashioned racism that has been seeded into society for centuries.
I don't think this is fair to most of these Trumpkins.
The concept of "racism" exists on a spectrum. When someone says the phrase "basketball player", the image that pops into my head is a tall lean black man. The phrase "medical researcher" makes me picture a white man in glasses. The phrase "English teacher" makes me think of a middle aged white woman in a sweater. That, by definition, makes me racist. It also makes me misogynistic. I have the self awareness to realize those facts, but I don't consider myself very high on the racist scale, and certainly well below the threshold of being maliciously racist.
When people say "racist", what folks tend to hear, especially when the term is used against them, is "maliciously racist". So while I agree being scared of losing societal power to "them" is, in fact, rooted in racism, I don't think it's fair to call these people "old fashioned racists". To me, that means malicious racism we see in movies that almost everyone agrees is terrible.
I don't think the average member of the Trump base is maliciously racist. They just lack the intellectual capacity to be self aware. We see that with posters around here like Jaw who says things like "can't find their peepee" as an insult referring to trans people, and lacks the mental capacity to be self aware enough that he can realize his views are being influenced by his biases.