Sanger's birth control movement did have support in black neighborhoods, beginning in the '20s when there were leagues in Harlem started by African-Americans. Sanger also worked closely with NAACP founder W.E.B. DuBois on a "Negro Project," which she viewed as a way to get safe contraception to African-Americans.
In 1946, Sanger
wrote about the importance of giving "Negro" parents a choice in how many children they would have.
"The Negro race has reached a place in its history when every possible effort should be made to have every Negro child count as a valuable contribution to the future of America," she wrote. "Negro parents, like all parents, must create the next generation from strength, not from weakness; from health, not from despair."
Her attitude toward African-Americans can certainly be viewed as paternalistic, but there is no evidence she subscribed to the more racist ideas of the time or that she coerced black women into using birth control. In fact, for her time, as the
Washington Post noted, "she would likely be considered to have advanced views on race relations."