Hating ISIS

MARCH 3 - Jesus said "Love your enemies." How do you love yet fight diabolical evil like ISIS?

The internet is flooded with real snuff movies: videos depicting unimaginably gruesome tortures and murders by humans who seem as callous as demons. Murder of children by torture, rape, fire, stoning, etc. and all in the name of a god. So what’s not to hate? Isn’t this exactly the sort of thing that justified war against the Nazi Germany and Imperial Japan? (e.g., see: rape of Nanking.) So how are Christians to voice their opposition to such evil? Do we call for a war of extermination? Jesus said ‘love your enemies’ but how do we kill an enemy without hate? Can we fight fire with fire? What is the basis of moral warfare, of just retribution, of necessary evil? What would the voice of Jesus say?