Communism in the 1930s was in its forming stages in all the world, except for the Soviet Union. This was only the political form of communism, however. The idea of the Brotherhood that communism inspired was seen throughout the world in different names. It was allowed to "infiltrate" young minds within the United States. Con men would see desperate, lonely people and convince them to join a brotherhood. This was especially prevalent in the inner cities, such as Harlem. Marcus Garvey is probably the most notorious man known for this. His back-to-Africa movement would take young willing black men and convince them that it was their duty to join the movement and give it money. The whole basis for the movement was to convince all African-Americans to join him and go to Africa to start a new nation. It was isolationism based on brotherhood and playing on the angers of all African-Americans living during that time.
Garvey’s movement was not all that successful, but his name became recognized and many people donated money to his cause. It was later found out that Garvey had been embezzling funds and that the reason for his movement was to put money into his pocket. This was allowed to take place because the ideas of cults and communism were not really in the minds of Americans. It was during the depression and people were not focusing. People with bad intentions were able to take advantage of this.
Communism was not a hated entity but a promise of being something larger. People wanted to feel needed and brotherhoods could offer persons the type of caring that they needed all while conning them.
This is nearly exactly the same story that Invisible Man is forced to go through. He is lonely and jobless, and the Brotherhood takes advantage of his talents for its own personal gain. Unlike most, though, Invisible Man is able to discover this before it is too late.