Wait until yall hear that in 1910s-20s folks in the US were racing on oval tracks made of wooden boards.

Even when the cars did not crash, racing on a board track was exceedingly dangerous due to flying wood splinters and debris, and due to the primitive tire technology and head protection of the era. In one oral history taken from a driver, he told a tale of wooden shards driven into the faces of drivers and riding mechanics, and sudden catastrophic tire failures caused by track conditions. Cars were fitted with anti-splinter devices to protect their radiators. Other safety devices also hadn't been invented yet (seat belts, roll bars, or fire protection). Drivers often were ejected from their cars and would fall tens of feet (several meters). Drivers and riding mechanics often were driven over by their own or another car. Pete DePaolo wrote in his book Wall Smacker that racing on boards was "a great sensation, tearing around a board speedway dodging holes and flying timber."

I noticed the kneepads.

A "normal" free throw shot is still taken differently since basically no player takes it as a jumpshot. A lot of the time their release is also a bit different.

Free throws are very high value shots and are worth getting good at. The reason people like Rick Barry endorse this method is the motion has fewer chances for variability; there's less room to slightly change your shooting motion because of the mechanics.

You are correct however that the most important point is what is most practiced. Most players don't want to risk changing things up significantly by the time they reach the pros. Though the ones who shoot FTs very poorly absolutely should try.