Part of the problem in this thread and a possible reason for so much confusion and acrimony is that it blends multiple interlocked but different issues.
For those who wear helmets is legitimate discussion about relative safety of various helmets, helmet standards, and helmet technological progress. They wear helmets and have every reason to be concerned.
Those issues don't affect those of who don't wear helmets, since we're unaffected. However we have legitimate concerns about the assumption that bicycling is dangerous, and that there are those who'd make helmets mandatory. We also have issues with image and how we're barraged by well meaning? folks who can't resist proselytizing us.
Lastly helmet wearer or not, we all need to be concerned with how bicycling and the "need" to wear helmets is view by outsiders, who may at some feel compelled to do something "for your own safety", or because of the externalities which many here insist on bringing up. That's a real concern because it extends beyond helmets, and can affect our rights to ride public roads.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.