Here, in FL, we have a choice.
No Helmet: MUST HAVE INSURANCE.
Helmet: NO INSURANCE REQUIRED.
Weird.............
That is sort of weird, given that the lack of a helmet will mainly only endager the rider and not others on the road.
Of course there is the argument, (which is also used for seatbelts), that a motorcylist with no helmet or a driver with no seatbelt will not make take sudden actions (like slamming on the brakes) to avoid collisions with others. There is some validity to that rationale, but more for seatbelts, than helmets, IMO.
Maybe the reasoning is that anyone who refuses to wear a helmet is an idiot, and therefore much more likely to have an accident? :-)