On Sunday morning, bombs ripped through a market in Baghdad, Iraq, killing at least 215 people. It is the deadliest terrorist attack in the world this year, and the deadliest attack in Iraq in nearly a decade. And, it was claimed by ISIS.

Yesterday, Shaun King of the New York Daily News argued that because the victims of Sunday’s attack were all or nearly Muslims, ISIS terrorists are not Muslims:

They weren’t attacked because they love Jesus or Taylor Swift. They were attacked by ISIS because the men who make up ISIS are evil and hell-bent on carnage and destruction …

Claiming a religion as cover for terrorism doesn’t make you a genuine follower of that religion. Yelling “Allahu Akbar” (which simply means God is great) before killing people makes a man a Muslim no more than yelling “Hallelujah” before a mass shooting makes a man a Christian.

This is an attractive argument, as it helps to separate the peaceful overwhelming majority of Muslims from the relatively small number of militant Islamists bent on sectarian domination. And, to a certain degree, it is an accurate argument, given reports that ISIS terrorists do not seem particularly well-versed on Islam.But there at least two problems with this argument.

First, most likely all or nearly all Muslims killed in Baghdad were Shias. As it happens, ISIS terrorists have been killing Shias for years. Why? Because ISIS terrorists consider Shias, for all intents and purposes, apostates. Why would this mean they are not Muslims? One might doubt the inspiration for ISIS terrorists to take seriously theological claims regarding Sunnis and Shias — perhaps their motivation is more tribal than theological — but it does illustrate that ISIS terrorists take certain theological claims very seriously.

Second, hatred violence between or amongst religious sects is not a new phenomenon (though it is not essential to religious sects, either). Sunnis and Shias have targeted each other for attacks before. Who then was a real Muslim? Neither side?  And then, who is a real Christian? If ISIS terrorists aren’t Muslims because they kill other Muslims, then couldn’t same be said of Catholics and Protestants during the Thirty Years’ War? Were fighters on neither side real Christians because they were killing other Christians? What of the American Civil War? Was the Confederacy, which claimed to be inspired by Christianity and wanted to create a Christian nation, just a bunch of hateful slaveowners? They would have certainly been surprised to hear that.

The truth is, the world is messier than we want it to be. Some people kill others in part due to inspiration from religious texts and traditions. Others are inspired by religious texts and traditions to stand opposed to sectarianism and violence and terrorism. The question is not who the real Muslim is; the question is who is reading or using Islamic texts or traditions in a way that present mortal danger to modern civilization. It is clear most Muslims are not, but that doesn’t necessarily make ISIS terrorists any less Muslim.