I had Cunobelin arguing the difference between a car passenger getting a head injury and a cyclist does also. what is going to hurt more (or words to the effect of).
From a first person perspective, there isn't any, and that is the argument for pro compulsion
When your brains are all over the road because you were one of the unlucky ones - statistics for other health benefits become academic
Let's forget trying to make sense of whatever it is you're arguing, and ask a different question. What, if anything, do you want from this debate, other than the opportunity to hang around with actual cyclists?