"So it's patently obvious it's not a Muslim ban."
Always remember, correlation does not equal causation.
There are many factors that may be why other Muslim majority countries are not included.  These factors can range from personal business dealings to treaty arrangements to limitations on political capital to just simple lack of reasonable justifications.  For example, one of Trump's defenses (or efficient expenditure of political capital) is that these countries were also specified under the Obama administration.