It is not white and black thinking, it is the idea of mutually exclusive ideas.
Think about a circle, a circle has one side right?
well now think of a circle that has more than one side, you can't do it
The IDEA of a circle and the Idea of multiple sides are mutually exclusive.
Similarly, the Idea of Monotheism and the Idea of Polytheism are mutually exclusive.
Islam is a set of Ideals that are mutually exclusive from other set of ideals, and Muslims have chosen to believe in the Islamic set of ideals, over other sets. Nothing wrong with this, in fact it is very natural thing to do.
A.Give me an example of Polytheistic religion.
B. Now you are trying to teach me 7 std social studies.