This commentary really seems like a hot load of garbage. And that's ignoring that fact that the OP is highly misleading in the title when the actual article is "Racism motivated Trump voters more than authoritarianism."
For example the "Symbolic Racism Indicators" (??) are basically asking the question of "do you believe systemic racism can ruin or bias free market capitalism?" and, if the person answers no, they are therefore racist. Is this really the definition a study should use to determine if a voter is racially motivated in their Presidential choices? I know conservatives who think capitalism is some unblemished beacon that can't possible be corrupted. This is more tied into their beliefs about the "purity" of free capitalistic markets than it is their beliefs on race. I find these questions a pretty damn high, and murky, bar to set for people to pass in order to not be labelled as "racist" or "racially motivated."
The questions also use phrases like giving blacks "special favors." It's literally trying to trigger white Republicans with some of this framing, which likely ends up biasing the entire study itself.
And more fundamentally, even if true, the study doesn't say Trump voters picked him due to racist beliefs, it says they were more correlated to the Symbolic Racism survey than the authoritarianism survey. But who was claiming Trump voters were motivated by authoritarianism in the first place? The commentator is creating his own strawman argument to knock down.
The motivation was an outsider who hated how Washington was run. And oddly enough, the study brings up in the beginning how being low-income (and thus finding Trump's economic message appealing) was a big, unusual factor in Trump's vote. But then the commentator proceeds to forget they ever talked about it in their final analysis paragraph of "which of these (factors) had the biggest influence?"
This is bad data.