This is our POTUS. He just makes shit up and lies his ass off.

Or....he intuited (correctly) that the details of campaign White Papers and binders full of policy proposals never, ever matter to voters. Campaign in poetry, govern in prose.

It's this scene, from Elf:

YouTube: Worlds Best Cup of Coffee (prazfighta)

If you make exaggerated claims, everyone knows that you don't mean them literally. It's the classic tool of salesmen and real estate developers - use "puffery" and hyperbole to sell your project, not specifics that a reasonable person would think you meant to be literally taken to be true.

If the Harris campaign made a big deal that Trump's "60% tariff" would cause X% inflation, they would look like fools - just like someone complaining that the "world's best coffee" sign was not actually true. It's not a statement that anyone is meant to take literally. It's intended to be just a signal that Trump wants to use tariffs as industrial policy, and not stick to the WTO-style approach to maximizing global trade in goods.