Final answer:
Dr. King exposed the idea promoted by white leadership to pacify poor white people through racial segregation and discrimination, which was dangerous to freedom and equality.
Step-by-step explanation:
The idea that Dr. King exposed and criticized is the notion that white leadership had used to pacify poor white people, which is to maintain the racial segregation and discrimination. This idea was dangerous to freedom and equality because it perpetuated a system of oppression and inequality, keeping marginalized groups, such as African Americans, from achieving equal rights and opportunities.
By promoting racial segregation and discrimination, white leadership created divisions among different racial groups, distracting them from the true source of their problems: the structural racism and systemic inequality. This tactic allowed white leadership to maintain power and control over resources, while diverting attention away from the need for social and political change.
In exposing this lie, Dr. King challenged the dominant narrative and called for an end to racial segregation, poverty, and voting discrimination. He emphasized that unity and solidarity across racial lines were essential for achieving freedom and equality for all.