African American Leaders in 1890s to 1920s had a different background, they surfaced in the post-civil war era and they aimed to pursue economic and education goals. W.E.B Du Bois, for example, defended that the only way to get equality between African Americans and White Americans was through education.
African American Leaders in 1950s and 1960s were from another time, they faced many and many years of segregation, they noticed that African Americans were mostly banned from getting education - the system the leaders before defended -, from electing representatives - some states limited African American votes - this way they aimed to achieve political and social equality.
A contentious issue at the 1787 Constitutional Convention was whether slaves would be counted as part of the population which they were deciding if they be under the representation of the states in the Congress or would instead be considered property and, as such, not be considered for purposes of representation.