the Dunning-Kruger is exactly about ability to notice
It seems like you are saying that every programmer ought to go out of his way to become fluent in algorithms, because without fluency he or she will never notice when their code is running slowly.
If so, I disagree. It requires no skill to notice whether code is running slowly--you needn't look further than my techno-skeptical dad muttering, "Jeez, this thing takes forever to boot up" as he regards his desktop with disappointment. I think this is what the grandparent commenter was talking about: if I'm not fluent in algorithms, but my dad doesn't think it's slow, then where's the problem?
"Premature optimization is the root of all evil."