Folks are free to choose what they want, it really is that simple.
Been on HD's for many years. In the 70's 80's 90's and early 2000's it really was no helmet, illegal beanie if you had to have a helmet. Leather jacket only if it was cold and most everyone rode in jeans, boots and a t-shirt.
Now a days, there is still a lot of that, but there are many more folks who ride HD's with a lot more gear. For me, it's an armored Vanson leather jacket, gloves, Draggin jeans, boots and depending what I'm in the mood for, a full face ( most of the time) a dot half helmet ( some of the time) or no helmet ( couple times a year ) if I'm in the mood and in a state where I dont have to wear one.