Conversation so far:
What was Bernstein's involvement with social activism?
he was also known for his outspoken political views and his strong desire to further social change.
What issues was he involved with?
His first aspirations for social change were made apparent in his producing (as a student) a recently banned opera, The Cradle Will Rock, by Marc Blitzstein.
What else happened?
His first opera, Trouble in Tahiti, was dedicated to Blitzstein and has a strong social theme, criticizing American civilization and suburban upper-class life in particular.

Question: Did he have any other activist interests?
Self-contained rewrite: Did Leonard Bernstein have any other activist interests other than criticizing American civilization?