Helen Keller was a socialist, not a communist. She was passionate about workers rights because she was shocked to learn many people became blind due to industrial and work conditions and lack of safety and regulations at the time. She was not alone in her views, many people were interested in workers rights at the time. On paper, socialism seemed like a good thing, history had yet to prove that it didn't work and would result in people losing their individual rights. It's ridiculous to judge people of a hundred years ago by our standards today and what we know now. J. Edgar Hoover was a paranoid nut case, having him keep a file on you meant nothing.
The Satan worshiping angle is pure nonsense, not only untrue, but silly. Please do more research before posting fake internet stories.