Not only does religion matter in determining who is a refugee. It's the law.

The Immigration and Nationality Act of 1965, which governs these issues, defines “refugee” as someone who has fled from his or her home country and cannot return because he or she has a well-founded fear of persecution on account of “religion” – as well as race, nationality, political opinion or membership in a particular social group. This certainly doesn’t let us use a religious test to filter otherwise-eligible immigrants out. But it does mean that when we’re deciding who to admit as refugees, religion matters.

So, when we think about religious refugees from the war-torn parts of the Middle East, who are we talking about? Right now Christians who are being singled out for religious persecution – beheadings, beatings, rape, forced conversions, enslavement. So also Yazidis, Mandaeans, and a few other smaller groups. Many Muslims are also displaced and suffering, but the Islamic State is not systematically targeting them for being Islamic. Our refugee policy should take that into consideration. This is not a “religious test.” It is a persecution test.

Not that Obama really cares what the law is if it is contrary to his wants. He doesn't.