Generally, it's because the manufacturer is honest and not interested in scamming people, but the middlemen are.

I'd imagine customs can identify "that came on a boat from China but says 'made in USA'" more easily than "the internal electronics in that charger aren't up to snuff".

I'm sure. It's just become so normal to doubt every aspect of a product, that it's strange to have some element of consistency.

Of course the label of origin still isn't likely to match what was on the product page. But that's almost a plus in helping to ID fakes.

Because when you import stuff to the U.S. it has to have the country of origin clearly marked somewhere. That's why it says Made in China.

Are chargers made anywhere else? Even with official chargers (i.e. that came with the new laptop/phone) I don't think I've ever seen a charger that wasn't "Made in China".

For a while at least, all the Samsung fast chargers sold in the US were made in Vietnam. If you got one from China, it was fake. Or a slow charger.