I have been a Catholic all my life and have never heard sincere Catholics “shout at each other” over matters of faith.
I have heard people insult and ridicule Christians. I have never heard fellow Christians shout at each other over faith.
Perhaps there was alcohol involved. Lots of alcohol.
This was before Benedict and the papal recognition of the Latin mass. People were getting pretty incensed over it. But in general you are right—true Christians don’t get angry over religion.
There’s a line at the end of a Philip Roth story: Never hit anybody about God, or something like that.