I've been in a skid at 60 mph (oil slick) and lived with some scrapes, thanks to the helmet
Nope. If you want to wear one, no one is stopping you. You don't need a law.
If you fall off a bike at 20 mph and hit your head on the side-walk, it could lead to some injuries -- at 80, it's death
If you're going 80 down the sidewalk on a motorcycle, you have other problems a helmet won't cure. Solid impacts at that speed and even less just transfer the blunt force to different parts of the skeletal anatomy, so something else gets broken--and helmets break in high speed (above 40) impacts as well.
I've been in a skid at 60 mph (oil slick) and lived with some scrapes, thanks to the helmet
Please don't confuse the abrasion resistance which benefitted you with impact resistance. Yes, you benefitted, because you had an ablative shield between your head and the pavement.
In the most notable example in my experience, the leathers saved me some nasty wounds, but if I'd had a helmet on, the outcome would have been worse. As it was, my glasses frame tagged the pavement and I got a cut in my cheek, but a helmet (of the style common then) would have abruptly turned my face into the pavement as I was sliding.
For now, let's say simply I prefer to be able to see and hear better, and have the reduced moment of inertia the absence of a helmet provides when I want to look around--which is often. There isn't much heavy traffic here, except in town, and that's the smallest part of North Dakota.
It sounds cliche, but I think I am in a better position to assess my relative risks than some legislator, especially after 35+ years in the saddle.
Helmet use, if you want to, is fine with me. There are occasions when I have used one myself, but I generally prefer not to.