AFAIK 60km/h let alone 60mph e-bikes aren't road legal in the Netherlands. 60mph is something like 95km/h. To give you an idea, most motorways are 100km/h in the Netherlands. To drive something that fast you'd need a full motorcycle license, insurance, etc.
Certainly they're not allowed on cycle paths.
Even if they were, Amsterdam has a citywide speed limit of 30km/h. That's under 20mp/h.