Hello! Can some one explain this to me in a simpler way?

Cultural factors also were used to justify imperialism. The same xenophobia that helped pass the Chinese Exclusion Act in 1882, and led to its renewal in 1892 and 1902, fueled imperialist ideas about foreign nations. Some Americans combined the philosophy of Social Darwinism—a belief that free-market competition would lead to the survival of the fittest—with a belief in the racial superiority of Anglo-Saxons. They argued that the United States had a responsibility to spread Christianity and democracy to “civilize” the world’s “inferior peoples.” This viewpoint narrowly defined “civilization” according to the standards of only one culture.