I understand that at the every end he acknowledges this is dumb, but I think the biggest issues faced by guys who follow that 6-6-6 rule is that they are immature.
Still a guy issue/hang-up then.
This is a dating rule by women for women, not guys.
Are you the type of person that believes only men can say foolish things?
That doesn't mean that teenage boys are either the origin or the ones perpetuating it. They're just an easy target to throw crap at.
You'd be surprised at how much "incel" terminology about how women are, started out as advice in self help literature by and for women, or in magazines like Cosmo. There used to be a whole subreddit for Cosmo's terrible relationship advice.