Ill make it simple - the crusader where very religios peoples. Monks actualy. and in there eyes killing muslims was a work for god.
same in jewish peoples. there are some crazy religios who think its a mitzva to kill arabs.
and there are muslims, who claim that its holy to kill unmuslims.
and what is common to all of them? they were a tiny precent in the total population. very very tiny. most of them are under wrong information too.
oh almost forgat. the Yugoslavia civil war. massive murdering of muslims, civilians, by christians soliders. not serbians soliders, families.
same in lebanone troughe the civil war. sabra and shatilla? christians killing muslims in the name of god and jesus.
even that muslims also belive in jesus. and the jewish god, the muslim god and the christian god is the same god, only the christian belive there in jesus after the bible end, and the muslim belive that mohamad was a prophet after jesus. the muslim belive in the same 'end of time' as the christian, jesus go get back to life and stuff.