It's a bit of a stretch to equate Paypal with "all American transactions." There are of course Visa/Mastercard (variable but about 2%), debit cards, Venmo, and older bank transfer technologies (ACH).
"all american transactions" - who cares what proportion it is? It's the most vulgar display of market power imaginable. "We will tax this large chunk of the economy." And I'm not even seeing anyone saying they won't get away with it.
It's really quite astounding!
So nobody force Americans to pay, actually, they do that voluntarily.