Why do people conflate "training" with "safety, proficiency and good judgement?" Are they fooled because training courses have those things on the syllabus? They shouldn't be. I have had a lot of training, but I was safe and proficient with DA revolvers at 12 years old, before there was any training outside of the military and LE. My Dad taught me, but I didn't get any certificate.
Years later, when I did get some serious training, I saw a lot of safety violations and some questionable proficiency and judgement among supposedly advanced shooters. In addition, have a relative who has been a USCG boarding team member, a small town chief of police and a big city deputy sheriff. I won't go to the range with him he is so sloppy and stupid. Training is not the point. Safety, proficiency and judgement are the point. And apparently training courses don't guarantee those things.
The signers of the BOR never went through a training class and they didn't write a requirement for it in 2A. They assumed people had common sense. People don't always have common sense nowadays, but they can't learn it in a class. "Stupid is as stupid does."