Although The Jungle is a work of fiction, Upton Sinclair did not exaggerate the true working conditions of those in the Chicago meat packing industry. Jurgis' character is like tens of thousands of real life people, recent immigrants from southern and eastern Europe who came to America thinking a better life was to be had.
Jurgis finds a job in the meatpacking plant so easily because the work is difficult and dangerous, and those who are injured or used up were fired or quit. The whole system of Gilded Age labor and profit depended on a steady supply of expendable workers, almost always poor immigrants who were exploited and abused.
Throughout almost the entire story, Jurgis' suffers from one personal and physical defeat to the next, his belief system finally morphing into Sinclair's version of social justice in the early 20th century: socialism.