Dr. Lev Watkins, one of the first black graduates of the Johns Hopkins surgery program said this about Vivien Thomas: "I think he is the most untalked about, unappreciated, unknown giant in the African American community. What he helped facilitate impacted people all over the world." Given the fact that Vivien Thomas never participated in a demonstration demanding civil rights or filed a lawsuit to enforce his rights, what did Dr. Watkins mean?