I think the basic reason for the rejection was that you added a significant amount of content to the post when you brought in the jsFiddle. This made it appear to be an 'invalid edit' (as the other reviewer marked).
In such a case, I think I would try to carefully word my edit description to indicate that you are bringing in code that the original answererposter meant to be part of the answerpost, and not just adding your own example. Not all reviewers might be aware of what a jsFiddle is, so it might not be immediately clear that when you "added" it in, you were actually maintaining the original meaning.
I do think it was an incorrect rejection, IMO. I just think that when they scanned it quickly, it struck them that you were "adding" an example which the original answererposter may not have meant.