Its so flexible that you have Catholicism, Christianity, Protestants, etc... But they all believe in one God, I am not sure though if they have the same bible versions. And they still bicker each other whose version of worship is the correct one.
In the other religion if you reject, i think depending on the law they are following. Yes you are punishable by death.
I guess my interpretation why they "switch" is because of the term
"Attack on my Faith"
That faith is the base or cornerstone of their individuality. Question and take that away, and it will crumble.