The list is long. First and foremost, it's never a good idea to forget that wherever there's intelligence there's always also stupidity. Then it's generally good advice not to confuse intelligence for wisdom. And between this and very long lists of cognitive biases, there's always the good old "Fuck ya, got mine!" Rule of Acquisition to remember. Et cetera.
Because a high IQ and a science degree does not mean that those people make good political decision. A lot of political decision making is driven by ideology and identity.
And, many of my friends who were doing PHD they used to follow dems, but are now supporting republicans after they got citizenship....
This is still many people, but only in that “many” is more than a “few.” It’s not the case that most people voted for Trump, or even most voters. Or even most phds who voted. 70% of phds who voted didn’t vote for Trump.
This is why they are facing political retribution. He is creating suffering for revenge, the national interest be damned. Trump is more interested in the credulous, easily manipulated, low knowledge and easily conned masses. Many high IQ tech and science people are them, but not most. There are probably a few that aren’t easily manipulated and are instead just self serving sociopaths buying influence and contracts - but compared to the scale of the nation, this is indeed a few.
That said I question both your and grandparents choice to look at only people who chose to vote. 68% of people who could have voted against this did not - either actively supporting it with a vote or deciding that they didn't give a fuck if it happened by not voting. Every potential voter either knew or ought to have known the result of this election result...