Because secularism denies certain parts of reality, it has no ability to see things that it deems "religious" as political or real or having anything to do with the material world. Therefore, it's sees Islam as a religion not a political philosophy of reality.
Secularism also does the same thing with Christianity. Therefore, because it places Christianity in the box of religion, it can no longer see it as a political theory that has anything to do with the material world.
As a result, it excludes Christianity from the thinking of the founding of America. The Americans who founded this country (with their Bible in one hand and an axe in the other) did not think this way and it now makes us vulnerable to attacks by Islam and by secularists like communism and fascism.
Biblical Christianity is a political and economic philosophy in and of itself and is the basis of all of our first ten amendments to the Constitution.
But because SECULARISTS have banned or separated the thinking of the Ten Commandments and The Sermon on the Mount, those of us who believe as the founders of America believed, have been banned or separated from America and been led to believe that we can no longer think or act as a true Americans. This is the great divide in American culture.
Our enemies, like Islam, communism, and Fascism are secular. Unfortunately, most people see these as the only options for America.
This is a very serious blind spot! And because it doesn't see certain parts of reality (the invisible parts of man, HIS SOUL, and the basis of Americans' moral character), it has no ability to see things that it declares as religious and political as real.
Therefore, secularism sees Islam as a religion and not a political philosophy. It also does the same thing with Christianity because it places Christianity in the box of religion only. Secularists can no longer see these belief systems as political theory. Therefore, they exclude Christianity from the thinking of the founding of America. This way of thinking makes will continue to make us prone to attacks by Islam, Fascism, and Communism.
Here is a short segment from the video.
Ayaan Hirsi Ali says this about Islam here and in her new book on DAWA.