Careful, I searched, that’s doctored. But, she did speak to the KKK. An unrelated Sanger quote:
“We should hire three or four colored ministers, preferably with social-service backgrounds, and with engaging personalities. The most successful educational approach to the Negro is through a religious appeal. We don’t want the word to go out that we want to exterminate the Negro population. And the minister is the man who can straighten out that idea if it ever occurs to any of their more rebellious members.”
– Margaret Sanger’s December 19, 1939 letter to Dr. Clarence Gamble, 255 Adams Street, Milton, Massachusetts. Original source: Sophia Smith Collection, Smith College, North Hampton, Massachusetts. Also described in Linda Gordon’s Woman’s Body, Woman’s Right: A Social History of Birth Control in America. New York: Grossman Publishers, 1976
http://prolife365.com/margaret-sanger-quotes/