> On a decent hill you can get a regular bike going >60mph.

This is not the same as being able to go > 60 mph anywhere, at any time, simply by pressing a button.

> When you get a bike like this you deal with the danger and wear protective gear just like you would with any other bike (motorized or not).

This only deals with the danger to the rider - it doesn't address the danger to pedestrians.

Pedestrian danger is the real issue but is already covered as it is illegal to ride bikes on the sidewalk in most cities (and this probably needs to be expanded).

Bicycles have long needed a dedicated infrastructure as they are neither cars nor pedestrians.