Does this logic extend to showering, pedestrians, and automobile passengers and drivers? All suffer as many or more head injuries per year than cyclists.
They may have more head injuries than cyclists(citation?) but unlike cyclists you're not at risk of being run over by a car after a fall in your shower and also you're probably not showering at 25km/h when you fall so the potential damage is much lower.
A head injury that results from speed or post-strike collisions is still recorded as a "cyclist head injury" so I don't think your points change the numbers.
Please note, I'm not trying to argue against helmets. The point is that arguments over helmets deflect the conversation away from the people sailing around recklessly in two ton metal boxes. Every time there’s a collision involving a cyclist, the question is "was he wearing a helmet?", not, "was the driver paying attention?"
The safest places to bicycle are in the nations where there's the lowest rates of cyclists wearing helmets. This is a car problem, not a bicycle problem.