Just out of curiosity, have there been reported incidents of the throttle ebikes seriously injuring or killing anyone in NYC? I would expect that might trigger a crackdown.
As far as the forum placement, it seems to me that OP implicates enough issues that putting it in general makes sense.
An implied question in the OP is whether ecyclists and bicyclists are "natural" allies or not. The answer that I'm taking from the NYC delegation here is that if the ebike is legal and being operated at speeds reasonable for bike infrastructure, then allies. If illegal and too fast, enemies, or to put it mildly, hazards.
I guess my question is whether NYC is special, or is it just ahead of the curve, and we're going to see these problems cropping up in other cities? Also, is this Manhattan specific?