I mean there is no prescribed limit of 25kph on ebikes. If you can't go faster that the laws of physics preventing you.
The USA has lots of different laws and legal limits to the UK . Some of them for the better some for the worse in my opinion.
As I understand the issue. The dispensation for ebikes was aimed at allowing the less able to enjoy cycling. Since then it's changed somewhat with most of the people I see on them being in the prime of life. Rather than being a two wheeled version of a mobility scooter.
Where should the limit be? If anyone asked me, which they didn't I would have set it at 12mph same as mobility scooters. But it clearly has to be somewhere and where ever it is someone will think it should be higher or lower.
Having got a dispensation from the tiresome matter of insurance etal. I don't think it's reasonable to campaign for a higher limit when you could just as easily get a faster bike and pay the insurance if going faster is that important to you. They go faster than I can manage for more than a few hundred yards , I honestly can't see why that isn't fast enough