Joe, there’s one problem with your article — either your examples are not even remotely parallel to what McEnroe said (such as Nick Saban), or else they actually prove his point (such as lighter boxers, who are kept in their own weight class for a good reason).
Why qualify it? Because it’s true. And it’s also not in the least shameful or dismissive of Serena to say that she would not beat the top men’s tour players. What would be dismissive is to take someone of her ability, determination, and skill, and render her ordinary against superior competition.