Islam is not a race, but Muslims often act as if they were a race. Nationhood, race, religion, language, patriotism, these concepts are often connected to one another.
Their loyalty is to Islam, and their people regardless of color are servants of the Arab race in a sense. Only the Arabic language is considered fit for their Holy books. They wear Arabian clothing to signify that they are Muslim, etc. They do not have loyalty to a country, but they do wish to create one large nation of dar-al-Islam. Of course each region with Muslims in it puts their own spin on the religion (with dervishes, quite literally), but all Muslims are Muslim first and black/white/Asian/etc. second.