I think the distinction is both easy to make and important.
Myths are widely held to be fundamental about a thing (but not necessarily true). Red herrings, on the other hand, are a distraction that draws your attention away from the actual matter at hand.
So that said, I think what you are trying to say is that contrary to the poster, you believe focusing on these myths is a red herring and there are other fundamental reasons that lisp popularity remains what it is. I suspect because you did not articulate the difference, your discussion got sidetracked into semantics because it sounded like you were saying they were "the same thing"
