Good song, Keith. Yes, not all Christmas songs have to be sweetness and light.
But I think the reaction of the English shepherds in your song and the story on which it's based says a lot about The Church's failure to communicate the meaning of the Christmas story (and the rest of the scriptures) to the poor and downtrodden -- partly because The Church has often not behaved in very Christ-like ways. I don't see your lyrics as so much an indictment of Jesus or of the Christmas story as an indictment of the "haves" (both clerical and laity) and how they treat the "have nots."