When people are killed for our religion and the stated goal of others is to kill us for our religion, that's "what"!
It was "what" in The Crusades, it was "what" in the Buddhist Uprising, it was "what" in most of the history of the United Kingdom - back before it WAS the United Kingdom and was just Britain, and more recently it was "what" in WWII.
We've seen what happened before. We'll not allow it to happen again!