I don't get the criticism. The guy obviously knows a thing or two about the sport of running and he's trying to convey something about it to the masses. How many times are people on here complaining about how someone said, "oh, you run, you should meet my friend so-and-so; she runs MARATHONS," as though pulling your butt across the finish line makes you a better runner than a 15-flat 5k runner. This is the exact point he's trying to make.
One takeaway: Almost everyone defines "serious" as the level that they're at. I wouldn't call 40mpw at peak "serious," but I have to acknowledge that 40mpw is probably much, much more than the average runner does.