Nicolae Roddy of Creighton University pointed out in an SBL paper that the Jews were not required to sacrifice to the emperor. It was a passing point, but it raises the question of why there would be such a massive difference between Christian and Jewish. Jews were just as monotheistic, just as intolerant of idolatry, as Christians, yet Christians were persecuted. I suspect that it’s the innovativeness of Christianity - Judaism was sanctified by long tradition and Christianity was not. Too, Judaism was recognizable to antique pagans in a way that Christianity was not - no temple, no sacrifice, a radically modified priesthood.