What evidence in the I have a dream speech supports the idea that African Americans were not treated equally in the US?

In Martin Luther King Jr.'s "I Have a Dream" speech, he highlights the systemic injustices faced by African Americans by referencing the "sweltering summer of the Negro's legitimate discontent" and the "shackles of segregation." He emphasizes that despite being promised freedom and equality, African Americans still experience poverty, discrimination, and social injustice. These references illustrate the stark contrast between the American dream and the reality of life for African Americans, underscoring the ongoing struggle for civil rights and equality.