Not at all sure I know what you mean, Louise. But I'm pretty sure the confusion has more to do with English-speakers not knowing enough Latin (Church or Classical) nor enough Italian to tell how to pronounce something.

In Latin Jesu's sound is "Yay Sue!" in classical and "Jay sue" in (Italianate) church pronunciation; other countries (including Germany and England) have their own traditions as to how to mispronounce Latin. Italian, "Gesù" is "Jay zoo" in the north and "Jay soo" from Rome south.

I doubt being American has anything to do with it.