No, they aren’t, in most US jurisdictions, which have specific rules for motorized bicycles (and often distinct rules for electric one.)
> If you have a motor on your vehicle it’s a motorized vehicle and needs to be registered and plated, driven on the road, given tickets like any other vehicle.
The fact that you don’t like the specific rules for e-bikes doesn’t make them a “gray area”.
My understanding is that the rules in NYC governing e-bikes and electric mopeds were very fuzzy until around 2020, but there is still some uncertainty.
Before 2020 most of the delivery "e-bikes" ridden in NYC were technically illegal and were subject to occasional/erratic police enforcement such as stings and seizures despite being about as ubiquitous as taxi cabs. This was controversial when I lived there.
I no longer live in NYC but since then my understanding is that the city and state governments have worked with delivery riders to clarify the legal status of their vehicles but there is still a bit of "gray area" in practice.