> Why did many high IQ tech and science people vote for their own defunding?

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.