No, they aren’t. The big brands’ sell limited e-bikes, but there’s a massive market for unlimited e-bikes that are basically electric motorbikes with nominal pedals to try and pass as bikes.
The US is a hodgepodge of local laws. AFAIK, there is no federal speed limit for e-bikes. The class 1/2/3 designation is optional. And class 3 often conflicts with local laws.