How Did Marx Criticize Capitalism

Marx criticizes how capitalism is all about the exploitation of the common workers. The Black Socialists also criticized how the car companies exploited their workers, especially on the African American group. In the documentary, one of the workers described a scene from his daily work. The young worker saw the older worker working beside him and all of the sudden felt frustrated of life because he would eventually end up like the older worker: spends thirty years of his life on the assembly line. The younger worker felt that the works are now a part of the machine and doing repetitive jobs everyday.
The Black Socialists are most concerned about the exploitation, which is also an important issue addressed by Marx. Marx had prophesied this situation