Comment by qu4z-2

The commonly cited source says, when you take the entire sentence, "We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil." and continues "Yet we should not pass up our opportunities in that critical 3%."

There's only so much you can do with people who will not even take the complete original sentence, let alone the context. (That said, "premature optimisation is the root of all evil" is much snappier so I do see why it's ended up being quoted in isolation)