Yea, that's the point actually. People willing to violate and kill others for a "greater good" will just seek for any reason to either be "excused" or to not have a bad conscience. A lot of those just seek for a way to either act violent or let their anger out. I mean well.. their whole family has been bombed by the US for example, it's reasonable for them to hate those people who killed your *innocent* family, but killing..? I'll leave that uncommented.

Furthermore, I haven't met a single Muslim who said/thought it's okay to kill an human for not sharing the same beliefs. I'm Muslim myself and I would never/never did hurt someone else if I didn't have to defend myself/someone else.