Correlation isn't necessarily causation. The majority of organ donors in the US are probably car drivers, for example. They also breathe oxygen, which can be fatal in the long term.
Cars have materials designed to deform in predictable ways to absorb shock and smooth the deceleration process in case of an impact.
Motorcycles have absolutely nothing of this sort. Body airbags can help a lot, but are still far from the safety that a car offers.
Personal opinion: motorcycles, as a means of urban transportation not sports or leisure, are for people who don't have an option and don't value their lives highly enough.
> "We were unable to identify any randomised controlled trials of parachute intervention"