My point is that the question was "What is the oldest Child ballad?"

It was not "What is the oldest item in Child's collection?" (obviously "Judas"), or "What is the oldest piece that Child thought of as a ballad?" (also "Judas").

My second point is that a popular ballad, which is what Child was interested in, has at least one tune, sung traditionally. Even if "Judas" really was sung, there is no evidence that it became traditional, i.e. was sung across more than one generation. "Riddles Wisely Expounded," on the other hand, exists in numerous versions and is known to have been sung traditionally.

I chose to answer the question in a helpful way.