"Without explanation"

I mean, sure, it would probably be embarrassing to have to say "because this was extremely stupid and nonsensical and entirely due to the weird hangups of the present guy in charge."

Perhaps the explanation is: to make space for other incoherent self-defeating policies like threatening the Fed that they'll increase tariffs if rates aren't lowered?

They're not weird at all given his worldview. It's Nazism. From his book to his public statements and actions, he consistently expresses this. The only thing he does not do is use the literal language that is not accepted. But the meaning and actions are the same. People are in denial.