Answer:
It means that being friendly towards oppressors will not have you get your rights. You cannot sit and wait for people to give you or others equal rights. The only proper way to get them to stop is by force, to hit them where it hurts. You could add the protests/BLM movement in as an example, the fact that policemen who kill innocent Black men and women typically walk free or get a slap on the wrist unless people demand justice.
The quote was made by civil rights activist Thurgood Marshall, the first Black man who served at the Supreme Court.