While I applaud this decision, I am not sure the explanation will hold up on the inevitable appeal to the Supreme Court.
However, I do appreciate the judge's ruling that the sticker played on the popular understanding of "theory" as a hunch, which could confuse students.
In its authentic scientific meaning, "theory" is an appropriate label for evolution, but what seems to get lost in this debate is the factuality of the physical evidence that evolution seeks to explain.
What the stickers said:
Well there's "origin" and then there's "Origin".
I don't think Darwin's theories attempted an explanation of our cosmological origins--only an explanation for the appearance of plant and animal new species over time, the fact of which has been documented beyond dispute.