> The decrypts also reveal that people such as Rosenberg, Alger Hiss and even Robert Oppenheimer were indeed working with the Soviets.

Actually they don't reveal this at all. The cables mention someone in New York, then someone else comes in and says that must be Julius Rosenberg, and thus the decrypts reveal he was working with the Soviets.

Even Rosenberg was working for the Soviets, there is no solid line between the decrypts and him.