Answer:
During the Hoover administration and the beginning of the crisis, many Americans became disillusioned with capitalism, since it did not respond to the needs of the population when the same economic system failed, that is, encouraged growth, but it was not way out for the needy.
Others were attracted by the visible activism of the Communists over numerous social and economic causes, including the rights of African-Americans, workers and the unemployed.
Others, alarmed by the rise of nationalisms in Europe (Germany, Spain and Italy), admired the early and firm opposition of the Soviet Union to these ideologies.
The number of members of the Communist Party of the United States increased from 7,500 at the beginning of the decade to 55,000 for its end.