This Church doctrine teaches that the white race has been given the right of "manifest destiny", They actually believe that a god has given them dominion over the earth and all its creatures. This is the mind frame that allowed these people to commit the most horrible crimes against other human beings.
They considered none whites to be inferior based on their race non christians as gods enemy. Since Christianity was new and represents the smallest faction of the major regious belief, most were unwilling to convert. The bloody christian crusades and enslavement of African people served to spread their bloody, racist and far fetched religion.