I believe he is right. The magic of 6 meals incredibly boosting metabolism for fat loss and one needing protein 6 times a day for building muscle is over exaggerated.
The average American may not get enough protein, have too many carbs and get most of their calories at night. This is bad.
3 meals evenly space time wise and calorie wise for ones goals with perhaps more attention to time around workout has not been proven to be inferior to 6 meals. For those who do not have the time or desire to eat 6 meals they are not screwed.
I think the current research show that at least 3 meals daily is superior to all this intermittent fasting crap people keep talking about. Maybe some merit for life extension by calorie restriction, but they could still probably reach their goals with 3 very small meals.
Functionally even if not scientifically though, eating 6 meals helps many people with fat loss or gaining muscle. Many people that need to eat serious calories have trouble getting in their calories and protein in only 3 meals and would feel incredibly bloated and lethargic with only 3 meals. For those trying to lose weight the discipline of eating many meals keeps them away from shit food and cravings and keeps them focusing on their next healthy meal. So the dogma is not without merit and has helped many to both lose weight when they want to and build muscle when they want to as well. The dogma is not going away anytime soon for these reasons alone.
So based on current research, as far as I know, do what works for you best you on a functional level and do not stress about the science until it more conclusively proves a clear advantage.