I guess you haven't been around this board long enough to know that I do racquet reviews for TW, have been playing tennis for over 30 years starting with wood racquets, have over 2,000 posts, and I believe I know my racquets pretty well. No need for me to do any research about racquet/body safety. I've lived it. I play with a PS 6.0 that's close to 13.0 oz, and know all about the benefits of a heavy, flexible racquet over a light and stiff racquet. Unfortunately, You and I are in the minority as evidenced by racquet sales. The majority of people who buy racquets want light racquets. They think a light and powerful racquet will solve all of their game's deficiencies. Most racquets are sold from their "pick-up weight" rather than from demos. People go to the store, pick up a racquet and swing it around, and think it feels easy to swing so they buy it. That's the sad truth. There's a reason why light racquets like the Babolat Pure Drive, Wilson H-Tour, and the Head LM Radical are some of the best selling racquets, and why heavier, flexible racquets like the PS 6.0 have been discontinued. Bottom line is: Lighter racquets sell better than heavier racquets.
If that guy's daughter (perhaps she's only 10 years old?) used a pro's low-powered, 14 oz. racquet, she would get creamed by her friend using a 10 oz. Prince Shark, and then she would probably quit tennis in frustration. Not much help for Wilson's future business.
BTW, before the PS 6.0 I used a 14.0 oz. Dunlop Max 200G for 13 years and a wood Dunlop Maxply Fort for over 10 years before that. Wood racquets for the general public were NEVER 18 oz. They were mostly around 14 oz. I owned and played with over a dozen models.