I think it's correct to say this executive order is not a, "global Muslim ban," but it's clearly focused on specifically stopping Muslims from coming to the US.
The "logic" for the countries selected is that they were already "countries of concern." [1] However, the executive order is written in such a way as to allow religious minorities in, even though they're from a "country of concern." The implication is that what makes the countries, "of concern," is their Muslim majorities. Otherwise, it would be unsafe to let in other religious groups as well.
There are all kinds of explanations for this, of course. The administration may have wanted to ban everyone, but didn't want the heat from the Christian right. They may have wanted to specify Christians instead of minorities, but they would look even more anti-semitic than they already do [2]. They may have written a sloppy executive order and not forseen how it would play.
They may also have used a list of countries from the Obama era as cover and written the order such that it would focus on Muslims with plausible deniability about that focus. They've already said they can add more countries to the list.
I think pointing out that the executive order could have banned more Muslims is worth saying but somewhat misses the point. The people who wrote this clearly think adherents to Islam are more dangerous than other believers. The fact that most Muslims can still get to the US does not change the nature of the order.
[1] http://www.cnn.com/2017/01/29/politics/how-the-trump-adminis...
[2] http://www.slate.com/blogs/the_slatest/2017/01/28/team_trump...