In the USA, there are more than 52 jurisdictions not including towns and cities and counties, but most (not all) states think of ebikes as being slightly restricted bicycles rather than motorcycles, as long as:

- they have functional pedals (otherwise it's a motorcycle of some kind)

- they require pedal assist at all times and have some kind of power or speed limitation (anyone can use this, or at least it is least restricted)

- they have pedal assist available and have a different, higher power or speed limitation (usually reserved for 16+ or something similar)

- they have a power or speed limitation that makes them suitable for adults only but doesn't require a driver's license or inspection

There are efforts to regularize these, and also efforts to make things more chaotic. For example, New Jersey decided that all ebikes require a new ebike license and vehicle registration. Across the river in New York, no ebikes require a license or registration, and may be operated on any street which has a 30mph speed limit or less... but cities are allowed to make their own rules.

California's laws are mostly regarded by bicyclists as being sensible, at least in every discussion I've seen that didn't feature a twelve year old trying to convince his parents to buy him a 70mph electric motorcycle. See https://thecyclistchoice.com/resources/california-ebike-laws...

In most jurisdictions it's only a motorcycle if it can exceed a certain speed or has a motor over a certain power in kilowatts. Or some combination of both.

recent news: https://www.bbc.com/news/articles/c89nyk4pz74o

There's no restriction on manufacturing e-bikes anywhere that I know of, as long as they obey the speed/power limits. (That's why it says 500W "peak" power - the continuous power limit in the UK at least is 250W but manufacturers just make the "peak" last for a very long time.)