That's a poor analogy. Sabathia didn't pitch to a 6.5 ERA, he pitched to a 3 ERA in this game, with a ridiculously high BABIP. If you want to make a relevant comparison, you have to extrapolate those numbers out over an entire season.
So instead of 20-0, 6.5 ERA, incredibly high WHIP, and an incredibly high BABIP, your analogy would have to be 20-0, 3 ERA, incredibly high WHIP, and an incredibly high BABIP. Not only would I call that effective, I'd call it a borderline amazing season, to have that low of an ERA with that high a BABIP. Now this is all worthless, because it doesn't actually pertain to the topic, but it does pertain to your analogy.
But, here's the key point. By definition, the word 'effective' only cares about the end result, not the process by which it was achieved. The end result was a 3 ERA, and a win. It wasn't pretty, and it wasn't accomplished by great pitching, but by the definition of the word, it was effective.