On a bike you are exposed. In a car, you are not. On a bike you travel around 30km average. In a car, up to 100km average.
When travelling at 100km with no seatbelt (legal in many areas), in a collision, you become exposed rather suddenly.
Fix the problem, styrofoam will not save you.
Pedestrians are on a sidewalk often with parked cars between them and the threat of tons of steel at velocity.
Scooters or anything going 15mph should not be on a sidewalk.
Is there a word for this? Theorizesplaining?
Similarly six-point restraints, I'm always confused why there's just a lap-and-shoulder belt in most cars.
I might be convinced to personally start wearing a helmet if an awareness campaign gained traction. As it is, I will take the additional risk to avoid looking dumb.
I personally believe that (personal adult) helmet laws are a violation of individual liberties but we should create laws that force bike/scooter sharing companies to make sanitary helmets available. It is better to regulate business behavior than personal behavior.