Assimilation is a way by which a set of minority group or culture gives up its own natural culture to take up the culture of the majority group that dominate the society the minority found themselves.
Explanation:
Assimilation brings about the infiltration of the majority's culture and norms over the minority culture. It relates to absorbing a group to adopt another culture or way of life where they can made to be full citizens of such country.
Moreover, the assimilation was relevant to the American Indians as a result of the Dawes act of 1887 which allowed the assimilation Native American Indians to be absorbed in becoming full citizen of the mainstream society of U.S
Several meanings could be agvined to this. On face value, Dr. King is saying that the men who lynched Emmett Till were morally bankrupt but hid behind Christianity and rationalized their actions for murdering Emmett for allegedly flirting with a married white woman.