Apparently in the Bible, God says "Do not test me". The Pope is a human and to try to be magically protected from bullets would be seen as testing God.
Assuming you believe in all that sort of thing of course.
Another point.Do you think christians are nasty for wearing crucifixes ?If jesus returns , as he is supposed to in the second coming.Do you think he will want reminded ?
Maybe God has decided that it's time for a new representative on Earth, and the incumbent does not want to make it too easy for God to make the change.
If there is a god, then he does not care about any of us!
As you say, the Pope cannot find it in his faith to trust him!
I bet he wears a bullet proof vest under that frock of his.