In order to Obtain their Slaves , many European Traders in the past Started a 'Business Relationship with African Leaders. The European traders will give the African leaders a sum amount of wealth in exchange of their help in capturing their own people.
To fulfill their end of the deals, many African leaders started to attack people from other tribes and take sold them as Slaves to the European Traders. The attack created hatred among the tribes and caused Political and ethnic rivalries within countries in Africa.
The answer is African Americans because the Civil Rights movement paved a way use for civil rights and liberties with their fights in the 60s, and it was led by Martin Luther King Jr. So I hope that help!