> As long as they'r not causing problems for other cyclists,
They cause problems. Maybe not every e-motorcycle rider, but most of them take full advantage of the power to out-accelerate other bikers and double the top speed of everyone around them.
Bike paths were design with typical cyclist speeds in mind. It's not uncommon to see a young kid flying down our local bike paths at 40mph or more on a modded e-bike, forcing all of the pedestrian and other cyclists to get out of the way as fast as possible. Worse, two e-bikers flying toward each other at 40mph in opposite directions is the same as one of them crashing at 80mph. Those speeds aren't really appropriate for bike paths, yet here we are.
I frequently run into young e-bikers or e-motorcycle riders on my local trails who are flying at unexpectedly high speeds. They're also tearing up the trails at a rate much faster than normal bikes because the rider has less control over wheelspin and is more prone to throttle out of corners than someone with a direct connection to the drivetrain.
I was a fan of e-bikes when they first came out, but the current incarnation of e-bikers and e-motorcyclists is quite bad in the real world. Again, not every e-biker, but many of the most prolific e-bike riders on my local trails are the same ones running modified e-bikes with too much power and manual throttles.