It seems you'd need work upstream a bit to prove your point. The conventional wisdom is that bicycle helmets are a "good thing".
Ok so 253 extra people will die from obesity. What about the ones that will not die but be disabled. What about those that don't die from falling of the bicycle but get disabled permanently or temporarily.
> They enforce the perception that cycling is dangerous.
Is that so controversial though. Cycling, absent dedicated bike lines, separate bike paths, and very well organized intersections is dangerous. Heck, driving is dangerous, riding a bike among cars is even more dangerous from what I understand. Now, I don't have the data, you seem to have some, so I can't point to any studies right of the bat here.
> Finally, as the study showed, they are designed to only be involved in an accident between you and the road. Not another vehicle.
Well ok, the helmet protects the head. Hitting the road because a car hit the cyclist or a deer or someone put a stick in the spokes, I can see having a helmet, even one not designed for automobile accident protection as a better idea than not having one.
One thing I can see is the false sense of security. I buy that argument. Someone before talked (sorry, can't remember who or where or if it was study or not) how when they were riding alongside cars and if they had a helmet, cars actually drove closer to them, and if they didn't, cars gave them more room. That's interesting I think.