The law needs to catch up. There are clearly good reasons for people to want extremely powerful e-bikes and they should be allowed to. They can't be treated like bicycles because they're too fast but aren't nearly as dangerous as motorcycles. We need a new category for light motorcycles.
The real problem, IMO, is that the law is generally not deferential enough to cyclists and already forces them off sidewalks, onto the street, and to follow traffic laws designed for cars. There's not much else to take away, and the rules right now are unreasonable enough that cyclists always break them.
I think what I would like to see are explicit requirements for insurance and licensing for powerful e-bikes, but made significantly cheaper so that people will actually bother. Requiring helmets for the insurance would also make it much more straightforward. We can require them to take the street or a dedicated bike lane and fully mandate that they have to be walked on sidewalks.