Not much of a debate, is it?
I think people with my views (and I know many people share my views) know what they are going to get when the come into a thread like this, which is a shame.
I think it is not much of a debate, like most threads on the topic are not much of a debate, because the pro-helmet party says
"Helmets are great, why don't folk wear 'em?"
to which the skeptics say "Why do you assert they are great then?"
and in reply are told "Here is my, or my mate's, anecdata"
and quite righty get told "That anecdata doesn't cut it, here is real data which proves... well... not very much at all about the effectiveness of helmets"
So yeah, it isn't much of a debate because there isn't really a debate to be had if you look at the data.
Your view appears to be that, for road cyclists, helmets make a difference in certain circumstance e.g. high speed cycling crashes on the road. I've asked "how much of a difference?" & "precisely what circumstances?"
I'm still waiting on an answer. An answer, which, if given definitively, would enable me to make a better informed choice about wearing a helmet or not. But most times the answer given will distil down to some or other variant of the unthinking "Well it's obvious innit?" which, I'm afraid, leaves the mustard startlingly uncut.