Why might the philosophy of communism have appealed to many 19th-century factory workers?
As the industrial revolution produced larger and larger factory systems, it also produced ever increasing opportunities for rampant capitalism to fall prey to its own greed, as is usually the case.
In the 19th century, especially in the US and the other "western" nations, the holders of wealth were able to seed the early expansion of manufacturing and/or processing (as in meat packing) so the means of production was held in the hands of a few, and they had a singular motive to expand their own wealth on the backs of the workers. In the early days of manufacturing, almost no proscriptions existed to regulate life in the factory, and Upton Sinclair's novel The Jungle aptly describes the result.
So the appeal that communism had on the economic level was obvioius...a more levelled approach to the means of production and the benefits of working to support that means. Vis. more wealth in the hands of workers as a share of their own labor.
Other factors also apply not as often discussed. In a novel such as Native Son the appeal to communism was based in racial inequality and persistent racism in American society. Thus, thought the novel is chronologically late, it points to seventy five years of supposed "freedom" for freed slaves and their descendents. However, freed slaves, Native Americans, and other disenfranchised poor had few options when the flight to northern factory jobs became numerous. The living conditions of these people further added insult to their labor.
In essence, all the factors that appeal to the message of a communist revolutionary political movement appeared in the US in the late 19th century and found many followers. The movement was unsuccessful in the tradition form (i.e. a Soviet-like revolution) because it never had the rooted beliefs to support it, the numbers, or the will to fight. By the 19th century, the American dream was firmly entrenched, and the abiding American spirit may have driven many of the poor to endure worse and longer just to have a shot to break through.
The reason for this is that the Industrial Revolution caused a number of problems for the workers that communism promised to fix.
During the Industrial Revolution, workers lost their control over their own working lives. They could no longer work when they wanted to and at their own pace. They had to come to work when the boss said to come and work at the pace the boss set. Workers also increasingly did not get all the benefit of their labor. Most of the money from the goods they made went to the factory owners.
Communism promised to remedy these things. It said that workers would once again be in control of their lives because the workers would be the bosses as well. It promised to allow the workers to get all the benefits of their labor because there would no longer be owners and bosses to take the money the workers produced.
Because communism seemed to be likely to solve the problems caused by the Industrial Revolution, that philosophy might have appealed to many factory workers in the 19th century.