True, but I think it's more complex than that.

First, I do not think the Vatican automatically represents the most conservative brand of Christianity; not at all times, anyway. Not now, for example. Second, beheadings seem rightfully barbaric and horrendous to us, but as terrible as they are, I think their impact is superficial in a way (though obviously not to their victims, and please make no mistake: I do not wish to live in a country that beheads people!). ISIS beheadings are a matter of form, a propaganda tool; a way to shock the West into action, and the local population into compliance.

But as for actual damage, compare their beheadings with the damage caused by some Christian leaders of First World countries who have been bombing cities in the Middle East and causing a lot of deaths. These conservative Christians sometimes describe themselves as "born again", surround themselves with religious phraseology, describe their wars as Crusades and name them with Biblical sounding names (Righteous Fury, Infinite Justice, etc, etc), feel their countries have a God-given right to shape the world as they see fit. Wouldn't people living in a city bombed by a Western country consider themselves the victims of Western religious zealots?

And if, say, we know Obama and Bush are NOT the same, are we not making the mistake of thinking every bellicose Muslim is exactly the same terrorist fundamentalist that cannot be reasoned with and must be exterminated? Maybe there are shades of gray with them, just like it happens in the West?