Specifically, it was the sole scrap of evidence for the "Out of England" theory, just as that famous pig's tooth was the sole evidence for the "Out of Nebraska" theory. Evolution actually gives you a framework that says some things shouldn't be found. If they turn up you either have a hoax, a misinterpretation, or something is really wrong with what we think we know.
Yup, when someone finds the blue dress is when they admit they were wrong, not before. Even then, they never apologize for mistatements, they never acknowledge they were wrong and they keep telling lies which have been discovered for decades afterwards - such as Haeckel's phony drawings of embryos. Evolutionists have a very big credibility problem.