I think a lot of smart people stumble around in person when arguing their point because their brain is moving too quickly for them to keep up verbally or because they are struggling with their in-moment strategy in debate or when questioned. Not saying that's why Trump does it, but, in person, without the benefit of being able to think through what to type and edit it before clicking the post button, I get tripped up a lot.
And...150 isn't generational giftedness - 175 is generational giftedness. Stephen Hawking's IQ is purported to be around 190 and I have a friend whose IQ is in the 180s (he is dying slowly and painfully from cancer so your prayers are welcome for his recovery). My own IQ has been tested a dozen times in several different ways because it was interesting enough to state educators that they wanted it measured carefully. And, FWIW, the answers diverged by more than you'd think. I've gotten scored at anywhere from 142 to 169 and the best guess is probably 155. But I don't consider myself generationally gifted. :\