The 25kph e-bike limit is based on a reasonable speed for a bicycle to go, and I agree it's a good middle ground - much slower than a fit cyclist can manage on the flat, or any cyclist can manage downhill (so within the speed envelope a cyclist will be used to controlling a bike), but fast enough to make decent progress as a practical form of transport. It's also a fast running speed, which we've evolved to survive a fall at without serious injury. The SCIENCE shows that e-bike accidents are due to them enabling people with little cycling experience and/or strength and balance impairments to use bikes, which they then fall off at low speed and when mounting/dismounting/doing unwise things with luggage, not due to their cruising speed being higher than typical unassisted utility cyclists.
Scooters, wheelchairs[1] and other personal electric mobility devices should, in my mind, be subject to the same restrictions for the same reasons, unless they're of a design that precludes efficient braking, where a lower speed seems reasonable. It's about predictability for other road users.
As cyclists we know that banning things simply because they're unusual and a visible minority use them recklessly is not the way to go. We shouldn't get jealous that scooters (both powered and unpowered) are currently fashionable and bicycles are not. They're all one less car, and should be encouraged. The leap from a scooter to a pedal cycle is much less than that from a car or bus.
The Rochdale story could easily be about a bicycle collision. We don't know the circumstances, other than that the operator of the faster vehicle should be considered responsible by default. Leaving the scene of the accident is clearly wrong, but also understandable since the vehicle was being operated illegally. (I'm assuming that a 'black electric scooter' is not part of one of the trial hire schemes - hire scooters tend to have distinctive livery.)
[1] The law seriously needs to be changed to make it legal to operate Class II and III Invalid Carriages in cycle lanes.