He may have been referring to the program described in the original post - 6 hours per day, 7 days per week of TKD for 12 weeks. I’d agree that the average person would be at a high risk of injury with a program like that unless it included several hours per day of academic class time on topics like the Korean language and history of TKD. Most people aren’t ready for 6 hours a day of physical exercise 7 days per week. Even when I was 18 years old and went through basic training, I’m pretty certain that the physical exercise portion of boot camp didn’t come close to 6 hours daily 7 days per week. There was a whole lot of classroom time and mental indoctrination.Not sure I’m ready to agree that “most” people aren’t physically suited. We can definitely agree that some folks aren’t. But even that would depend on the program. Wouldn’t it?
That said, you could definitely come up with an appropriate intensive 12 week training program for most people. It’s just that the implementation of “intensive” would differ considerably based on the population you were targeting the program for.