“I’m a ‘never Trump’ guy. I never liked him.”
“My god what an idiot.”
“I find him reprehensible.”
"I go back and forth between thinking Trump is a cynical asshole ... or that he's America's Hitler".
I'm pretty sure it's more sinister than that. He's an authoritarian, and Trump values loyalty more than anything. A rival authoritarian is a bad idea. Keep your friends close, your enemies closer. Trump needs people to throw under the bus.
History shows that Vance is likely one of those people. Vance would be pretty stupid to not fall in line, but when it comes down to it, it won't matter. He's already offended Trump.