Having looked at the words in the DT I think that the song is unlikely to be about John who I believe was nether a bastard nor homosexual but Richard. The gayness fits and the French references fit. But he was not a Bastard.
Poor John has had a very bad press. In fact as kings go he was a very good one. His legal lagacy was excellent. He was, however dogged by bad luck. The Elizabethans in their embroidery of the original Robin Hood ballads set the tone for the way John is thought of in modern times. The real "Bastard" king of that era was definately Richard. He did not speak English and only used the country as a means of raising money to finance his wars against the Turks.
Hey! I feel better for that