Final answer:
Martin Luther King Jr. believed that African Americans were victims of broken promises because despite legal decrees for equality, they continued to face widespread discrimination and injustice. The disappointments from religious leaders, government actions, and societal attitudes towards civil rights echoed the sentiment that African Americans were promised equality that was not yet realized.
Step-by-step explanation:
Martin Luther King Jr. described the Negro people as being victims of a broken promise because after the Emancipation Proclamation and constitutional amendments promised freedom and equal rights, African Americans still faced systemic racism, segregation, and societal betrayal. The civil rights movement under leaders such as King and organizations like the Student Nonviolent Coordinating Committee (SNCC) sought to rectify these injustices through peaceful protest and public civil disobedience. King's passionate calls for justice, following a lineage of unfulfilled promises, were centered on achieving the rights that African Americans were due as both citizens and human beings.
King expressed profound disappointment at the lack of moral support from white religious leaders, the failure of President Kennedy to fulfill his promise concerning a second Emancipation Proclamation, and the challenges facing the nonviolent approach within the movement. These reflect broader sentiments that the American government and certain aspects of society had not lived up to their moral and legal promises to ensure equality for African Americans.