I daresay that a difference in opinion like that would probably not trigger most people back in that age in the same manner it seems to do so now (on both sides - I'm not picking on one side here).
That said, Benedictine monks would not be at or near the top of my list for people who would get all triggered, angry, and go to war over you disagreeing that God exists.
Yes, people fiercely defend what they love and believe. But it's possible to do so graciously and firmly without being angry or freaking out that someone disagrees with you (I am not referring to you specifically, but you, myself, our readers, mankind, etc).