ISIS is Evil
ISIS, the Islamic State of Iraq and Syria (at times called ISIL) is evil. Those who try to explain, accept or rationalize this evil help to perpetuate it.
After the beheading of James Foley, after the murder of Christian children, exactly how much more proof does one need?
It is important to be honest about the evil in the world, if only so you know how to identify it when you see it. It will also help you point out those who aren't honest about it, and, by extension, defend and support it.