Question

A. “In what case is this said? With regard to the seven nations. But Jewish informers, and the heretics, and the sectarians, it is a commandment to destroy them by hand and to lower them into the pit of destruction, because they persecute Israel and turn the people away from God, like Jesus the Nazarene and his disciples, and Tzadok and Baitos and their disciples, as it says (Proverbs 10:7), ‘the name of the wicked shall rot.’” (Maimonides, Laws of Idolatry 10:1)
He writes that Christians should be killed directly. I imagine that because he lived in a Muslim environment it was easier for him to write that. Do you think this is nonsense?
B. In your opinion, are there any ‘sacred cows’ that must not be slaughtered?