I think the reference to professional shooters is only to point out that even they can't fire a pump as fast as an auto. Yeah, it's "close" but it's STILL slower, and that giving the pump every possible advantage.
Point being, if they can't do it, it's hopeless for the common man.
An archery analogy.... I know guys who can shoot bows that have inherent weaknesses in their accuracy potential (like ultrashort brace heights) just as well as they can shoot much more forgiving bows.
That's a fact. What's not a fact, is that their ability to do so somehow suggests that those bows are "just as accurate" as the more forgiving bows in the hands of a less than good shooter.
We put them in the hands of the best in the world and say "See! I told you!" but those things simply to not extrapolate to "real" people.