Americans are exhausted by political news

This is the result of a firehose of falsehood, a staple of the Russian propaganda machine. It's the backbone of Trump's political career. He constantly says blatantly false, absurd things for 4 reasons:

1) It keeps his name in the news so that people who don't follow politics recognize it, even if everything they know about him is from The Apprentice. In marketing, name recognition is more valuable than having the best product.

2) It exhausts his opposition. It takes much more effort to disprove something than it does to make up bullshit. By the time something actually worth fighting for comes up, his detractors have no energy left.

3) It creates so much noise that people don't know what's true and what's not, discouraging them from participating in politics at all and leading them to believe that all politicians are full of shit. This has the added benefit of feeding into Trump's "I'm a political outsider" narrative.

4) It misrepresents what's true and what others believe. If you hear the same headline from 5 different sources, you're more likely to believe it's true. Even if it's false and even if 2 of those sources only mention the headline to try to disprove it. Similarly, the more often you hear a stance the more likely you are to believe it's a popular stance, emboldening you to act if you agree and discouraging you if you disagree.