Some people really, really, hate being told what to do, especially when it's a (in their opinion) significant inconvenience to prevent some (also in their opinion) very unlikely hazard.
It's baffling to me too, especially cyclists without helmets. Part of why I don't cycle is because, yes, helmets are annoying, but it's too dangerous to do it without a helmet.
It’s really not that dangerous. If you’re a safe rider, riding in relatively safe environments, cycling is about as dangerous as jogging. And yet you never see anyone jogging with a helmet.
There was a recent video about this that summarized my thoughts on helmets
I didn’t say jogging was faster than cycling, I said it’s about as dangerous. Which is what the data from the study cited in the video shows. So i’m not sure why you’re bringing up speed.
Are you claiming that jogging is as dangerous, in terms of level of injury as cycling? That seems implausible to me. I would be curious what you base that on. My initial assumption was that your belief is that you're as likely to suffer and accident while jogging or cycling.
Why would you do this? (See also: cycling without a helmet.)