Why was it such a big deal to have different colored skin in the times of Martin Luther King Jr.?

During the time of Martin Luther King Jr., different colored skin, particularly in the context of Black Americans, was associated with systemic racism, segregation, and discrimination. The societal norms upheld by Jim Crow laws enforced racial separation and inequality, affecting access to education, employment, and basic civil rights. King's activism sought to challenge these injustices and promote racial equality, making it a pivotal era in the fight for civil rights and social justice in the United States. The struggle highlighted the deep societal divisions and the urgent need for change.