No liberation without repression?

"How difficult it sometimes is to know where the black begins and the white ends." Booker T. Washington, Up from Slavery (1901)

“How difficult it sometimes is to know where the black begins and the white ends.”
Booker T. Washington, Up from Slavery (1901)

The brilliant and provocative Randall Kennedy, Harvard Law professor, has written a brilliant book about about people who do not defend their ethnic or cultural background. Otherwise known as “race traitors” or “sellouts”. In his wonderful book “Sellout” he describes the history of the black person who has compromised their racial identity for their own financial gain. He argues this is at the wider cost to the black community. He defends the right of the black community to ostracise sellouts and argues that the liberation of black Americans required a collective back-turning on treachery.

“There is much ostracism that is good: ostracism of racists, misogynists, fascists and purveyors of other hateful ideologies. We rightly describe as progress the repression of such ugly ideas and their attendant modes of conduct.”

He argues that the civil rights movement relied on creating a climate of fear amongst black people who would otherwise have sold out. Without the fear of black-on-black reprisal, blacks would have continued to ride the buses in Montgomery, Alabama in 1955, and the boycott would never have happened.
Do you think that we are right to ostracise those whose views offend us? Can we defend the right to free speech, but legislate against their “attendant modes of conduct”?