I do not buy that argument, what type of person buys an E-Bike, a person who needs a little assistance with cycling, I have nerve damage in my legs and hands, that's why I use an E-Bike now, I think you will do more or equal damage if you are a fitter person roaring down the hills on a normal bike.
Point is, this is about profit, not about facts, if a trail is going to be damaged it's likely to be damaged by both types of bike so charge the same for both types of bike, we already have a divide between bikers, this just deepens the divide and is unhealthy and shouldn't be encouraged.