The piece that Confronting Racism will discuss in the study session on Yom Kippur is called "Why We Went: A Joint Letter from the Rabbis Arrested in St. Augustine."  [https://rac.org/why-we-went-joint-letter-rabbis-arrested-st-augustine]  

The letter  was written by the 17 rabbis who were arrested in 1964 in St. Augustine, FL for assembling in an integrated group as a protest against racial segregation, discrimination, and violence