Final answer:
Blacks and Whites didn't shake hands due to longstanding societal norms underpinned by white supremacy and black inferiority, segregation laws, and the separate but equal doctrine prior to the 1954 Brown v. Board of Education ruling that began to dismantle these barriers.
Step-by-step explanation:
Whites and Blacks didn't shake hands because of the deeply ingrained racial segregation and societal norms that dictated their interaction, a consequence of longstanding white supremacy and black inferiority. Up until 1954, when the U.S. Supreme Court ruled segregation unconstitutional in the landmark Brown v. Board of Education case, Blacks and Whites lived under the 'separate but equal' doctrine.
Throughout this period, African Americans faced systemic racism that relegated them to inferior status. Black soldiers in the Union Army during the Civil War were given menial jobs and kept separate from their white counterparts. Following emancipation, the rules of Jim Crow legally enforced racial segregation, influencing all aspects of life including social interactions, with blacks experiencing continuous discrimination and indignity in public spaces.
The relationship between racial groups also affected the notion of progress and unity, as highlighted in Washington's controversial address, which suggested that Blacks and Whites could work together for mutual progress despite societal separation.
This separate existence was reinforced by shared values among Whites, like the belief in white supremacy, and the fear of slave uprisings that underpinned racial hierarchy. Discriminatory practices were not limited to the South; they were part of a national ethos that allowed for events like the White League and the Ku Klux Klan to unite in common racial animosity, as depicted in Thomas Nast's political cartoon.