Is not circumcision pretty routine here in the US? Two of my children were immediately given circumcision. My oldest was not because he was premature and there were more important issues. But I do not recall being asked my opinion on the other two.
Arguments for banning circumcision come down to saying, “What Jewish people believe God told them to do - not just in passing but as the very sign of their people’s unique covenant with Him - is too horrible to be permitted.” That is like saying to observant Jews, “Your ‘god’ is evil, and so are you if you follow what you believe was commanded.”
One can easily see why Jews would consider this deeply insulting, and even threatening, since a reasonable next step is to conclude that evil people with horrible religious beliefs and intolerable practices should be eliminated.