Answer:
Because at the time, the American army was still segregated, and African Americans were discriminated in the army, even if they provided the same service for the country during the war against Germany and Japan.
Fortunately for African Americans, the army was desegregated after the war, and in the following decades, the Civil Rights Movement would lead to desegregation in most public and private places across the country, especially in the South.
Answer:
Although Progressivism brought greater efficiency to government, established a more equal playing field for business, and increased the political power of ordinary citizens, the biggest failure of the Progressive Era was its exclusive nature. The Progressive Era coincided with the Jim Crow era, which saw intense segregation and discrimination of African Americans. The legitimacy of laws requiring segregation of blacks was upheld by the U.S. Supreme Court in the 1896 case of Plessy v. Ferguson. The ruling on Plessy thus allowed segregation which represented the institutionalization of the Jim Crow period. Everyone was supposed to receive the same public services but with separate facilities for each race.
so basically, it failed to solve racism and segregation.