What in the wild hell gave you the idea that the US banned crypto? That's the craziest thing I've heard, our government has come out and said they are working with exchanges to make sure that they limit illegal use but that just shows they're seeing this as a here to stay thing.
most probably it is like everything else and the reason is simple: FUD.
throughout the past couple of weeks that they have been trying to manipulate the price and were trying so hard to push it below $10k once again, all kinds of crazy things were being heard all over the internet about bitcoin. US banning bitcoin FUD is not surprising really!