Time to confess,
My first street bike was a Harley and I wore the costume. I was young and impressionable, letting peer pressure, trying to fit in, and the image influence me to make bad decisions about gear even against my older brothers advice as an experienced rider and racer.
After witnessing the results of relying on image and ego rather than training and gear I changed my ways. I'm still not ATGATT, but now always wear at a minimum a modular helmet, boots, gloves, and almost always a jacket and long pants. I do sometimes do my short sub 40 mph commute in shorts and a shirt in hot weather when riding my Ural. When on 2 wheels, jeans and jacket stay on.
I sincerely believe most gearless riders don't put much thought into it, being more of a monkey-see-monkey-do kind of thing.
"Take care, sir," cried Sancho. "Those over there are not giants but windmills".