The OP is correct wrt powerful e bikes sharing space with pedestrians and normal bikes.
They are a different beast, heavier and noisier. They have much higher speed limit, and require less effort (some models need no pedal power) to travel. This, alongside the rise of delivery services, encourages people to overspeed (more than 20mph).
15mph is roughly the limit of what makes bicycles safe for mixing with pedestrians, but beyond this speed, they aren't that different from a motorbike in terms of road design considerations.