I think something that confuses both Christians and non Christians is that while we are not allowed to pursue vengeance or revenge we are allowed to pursue justice and justice may very well look like setting someone on fire or sacking a city.
Christianity is most certainly not pacifist in any way shape or form but the object of the exercise is justice.
One age is the age of the martyr the next is the age of the crusader.
All we're doing is defending, so get ready for war.