It's rather astonishing that all the safety regulations for cars manage to exist in the same legal system that allows motorcycles on public roads at all. Last I read the death risk ratio was about 24x.
In a car you tend to hurt other people including any kids, etc that may be along for the ride.
As per sibling comment, maybe the only reason they are tolerated is that the risk is statistically largely to the rider themselves.
IE the person taking the risk is largely the target of the consequences.
If motorcycles somehow magically penetrated into peoples cars in a crash I think people would rule them out pretty quick.