That was a copy from another site, and the poster didn't referrence anything. He just said that the Hebrew word used was not the Hebrew word for "child" it was the Hebrew word for some of apprenticeship age. I can't verify this though. I thought it was an interesting viewpoint, and it DOES make sense in the context.
These people had just witnessed a miracle of God and were mocking it and his prophet. They knew what they were doing and who they were doing it to. Also interesting is that the word used at the end is claimed not to be the word for "killed", but it could have meant "injured".