Not saying is the only way! It can be done many different ways. My OPINION is that this is the most effective way to learn the punch and my reason why I believe so. As for Freddie, I just thought it was a good explanation, not that he is always right (Arlovski). But, I think he is pretty qualified to give advice on punching.......?
I have seen many guys get KO'd by punches that are not "technically" correct. If the end result is the other guy gets KO'd..... who fuckin cares if you threw a "incorrect" punch. But someone who fights or has the ring experience (you do) learns what works best for them, a new striker (lot's of the guys on these forums) do not have that to rely on, so proper technique is probably a good idea?