Let me throw a little more fuel on the flames:
I ride an ebike because at my age my knees are not happy climbing hills. Without the electric assist I would no longer be ridiing. I ride it only in pedal assist mode, not via a throttle. So much for the OP's snide remark about "keeping up with my age - blah blah blah."
My bike meets all the MN statutes for ebikes, is considered to be a bicycle under the law and can be used wherever a bike is allowed - unless a local venue restricts access by ebikes.
We have an extensive network of beautiful wooded MUP trails that I ride several times a week. My normal speed is about 14 - 15 MPH, which seems to be reasonable on a busy MUP. I have only encountered one idiot on a go-fast ebike. I caught up to him at a rest area, and talked with him about the bike - double shock fork, beefy frame, monster battery and motor. He claimed 40 MPH+ on the flat. Illegal in MN but still on the MUP trail. But - the problem is not legislation, it is enforcement. Nobody patrols the trails for any reason other than maintenance.
Considering the ongoiing emphasis on automotive power and performance it is not surprising that the ebike companies and enthusiasts are jumping on the go-fast bandwagon, even though the product doesn't meet legal guideliines in many states. Again - no enforcement.
And as another poster observed, there is also the danger of high-speed pedal-powered bikers on the trails - they scare me more than the joggers and dog-walkers!
Since I have no control over the actions of others, I practice defensive driving in my car, and assume that every other driver has the potrential to do something stupid at any moment - and very likely will. I ride my bike the same way.