During european colonialism, ethnocentrism classified whites as normal, and nonwhites as abnormal and inferior, to justify:

According to William Sumner, he believed that Ethnocentrism is part of human nature. During the European Colonialism, French colonizers in St. Dominigue believe that they are superior because they are white. This idea was born because Europeans(in general) have white complexion and comes from middle and upper class families in Europe. That is why they see the blacks or the nonwhites inferior because they did not bore the same physical attributes.

That is true! many fish species traveled to the u.s. because of it.