Paul is one of my heroes. What a voice! A great man with a wonderful gift, who tried to improve the lot of people everywhere, and was abused, and forgotten. Also, an active campaigner against anti-Semetism (his wife was Sephardi).
He was Communist, but also a patriot and never compromised his principles. Someone like that is dangerous. Now if he had shut up and behaved like a good little boy, maybe he would be a household name. Basicaly that I think is what they were threating him with.
As to films, he vowed never to play in one again until better roles were written for blacks, because he hated what he was given (like Sanders of the River, which also included a certain Mr. Kenyata).