Here’s an good example of the “How” the OP asks:
https://www.cnn.com/2024/04/18/politics/bill-barr-donald-trump-vote/index.html
So you can have direct, first hand knowledge of how far Trump would go, be able to verify that the claims he made to attempt to overthrow the government were bogus, be attacked by him, hear him threaten you directly for being disloyal, but when it comes down to choosing between your team (R) and (D), the Democrat is obviously worse for “reasons”.
“I’ve said all along given two bad choices, I think it’s my duty to pick the person I think would do the least harm to the country,” Barr replied. “And in my mind, I will vote the Republican ticket. I will support the Republican ticket.”
“I think the real danger to the country — the real danger to democracy, as I say — is the progressive agenda,” he continued. “Trump may be playing Russian roulette, but a continuation of the Biden administration is national suicide in my opinion.”
I personally read this as “I hate Trump, but only one party will work to ensure that I, as a wealthy, white, male Christian, will have perpetual deference and primacy in our society.”