The very real communist front the Sierra Club started the Envirocult in the 70s. Then they forced it on Berkeley who picked up the Envirocommunist baton and started pumping out Communist indoctrination enablers. Who then spread out across the nation promoting the Envirocult and Envirocommunism like a disease.
Watched it happen step by step.
I was a member of that organization until I moved to Knoxville in 1987 and started attending chapter meetings where the primary activity discussed was how to stop various business developments and promote various forms of socialism. Then I dropped my membership. Sad, too, because the Sierra Club sponsored al lot of great outdoor and wilderness trips.