It is simple. Communities of people striving in a tolerant way, flaws and all, to live up to good moral principle should not be left to die. The ability exists to recover such communities to a place more in favor of such perspective. That means, to me, letting go of those world trouble spots simmering over in violence. Military action is not a solution in those circumstances. The condition of intense strife is a choice made in those areas of the world. The first world is not blameless in this. Regardless, at minimum, christian communities should be briefly defended and then fully relocated to safer lands.
See the article, Vatican backs using force against IS.