Open carry is not dumb in itself. Open carry to just show off some gaudy ass pistol or a baby 380 ust because you can is dumb in my humble opinion.
Granted, I thought basically the same as you when first really exposed to it. The long I was exposed to it and watched it in practice in everyday life, it made more sense. It did screw with me at first. My instant mental response was to quickly evaluate the person carrying and assess if that person is a threat or not and what will be my first response if they are a threat. A few years later, during a Vet group bitch/discussion/therapy session, I talked about this first exposure to open carry. One of the old 'Nam Vets started laughing at me. "You've got PTSD, fucker!" "I've spent time with you and I know how you are when we go out to eat. Why do you think we have a damn round the rosy when we sit at a table or booth? We're both trying to get our backs to the wall and a good view of the 'lay of the land!"
He dogged me about that at almost every damn meeting, until he had a massive stroke. At least it killed him outright. It would have been pure hell for that guy to have been a invalid.
I don't think I have it. I think it's just me being me! LOL!