Why is Jurgis arrested and jailed in the novel, The Jungle?

When Jurgis’s wife, Ona, comes into contact with a boss at the packing house who finds her attractive, he tells Ona if she does not have intimate relations with him, he will make sure her entire family is blacklisted at the packing houses. Frightened, Ona submits. When Jurgis finds out the boss took advantage of his wife, he beats him up. Jurgis is arrested for assault.