There are people who believe that much of modern leftism boils down to anti-western sentiment.
For example, ex-KGB agent Yurl Bezmenov has gone on record (video, YouTube, 1h 20m) stating that the majority of the KGB's activities were centered around spreading anti-western ideology in the United States.
He stated that the goal was to demoralize at least one generation of American youths to go against their self-interests and the interests of the country. According to Bezmenov, the Cold War perhaps not coincidentally was happening at the same time as the Western counterculture movement, which has evolved into modern day leftism.
This kind of theory is often dismissed as paranoia; however, Bezmenov clearly states their goals and methods and how successful the program was.
Is there any credible evidence that proves or refutes Bezmenov's statements about the KGB's role in creating/supporting the leftist movement primarily with the goal of demoralizing the Western society?