Because this "word salad" nonsense is a delusion of the illiterate right. She's quite an engaging orator. If you like scrambled words and phrases, though, Trump has done quite a few.
"I'm very highly educated. I know words. I have the best words. I have the - but there's no better word than stupid."
“They can take out a city. Let them take – let them take out Los Angeles. Let them take out San Diego. That’s – this is a very small price to pay, and it’s going to be over with very soon. It’s essentially almost over with.”
“But then the – then the virus came in and the world is a different place but we’re now getting back and one of the reasons the market’s doing so – it’s almost at the point that it was at prior to the plague – almost.”
When you look at his speech patterns (even in writing, where he gets a chance to edit them!) the implication is strong that he doesn't have the attention span to compose a complete, clear sentence.