This is not how Scrum, Agile, or metrics work. Incompetent management doesn't need to be generalized into some sort of indictment of things beyond incompetent management.
That’s how every response to this sort of criticism: when people criticize capitalism, response is “that’s not a true capitalism”. When people criticize policies of communist regimes, defenders of communism say that these regimes are not instances of real communism. When majority instances are not supposedly true instances of whatever-is-in-dispute, then one should stop coming up with it-is-not-true-X.
Well when what you're criticizing is a caricature and a strawman, it's perfectly reasonable to point out that you're in fact criticizing a caricature and a strawman.
Specifically, this is the no-true-scotsman fallacy. It should be noted a fallacious argument doesn't mean that a non-fallacious argument doesn't exist for the same claim.
