The bit about risky sporting activities is not the same as road use in choice, demographics or population.
By that I mean if you want to do skydiving that's your clear choice, you're fit and well and trained in that activity, and there's a few thousand of you at most.
However if you want to get from A to B then whether it be on motorbike, car or bus, you're without choice a road user, you could be any age and health condition and there's millions of you.
So to protect this large number of citizens the state has road laws which are pretty reasonable really.