Upton Sinclair had a huge agenda. At no point did he ever discuss how the Chicago packing industry got the way it was. Chicago has had a long reputation of corruption. At the turn of the century, opening a meat packing plant in the Chicago area required personal permission of the Chicago mayor, and he didn't give any out to anyone but his close friends. This was a perfect example of a government regulated market. The current operators knew that they were safe from competitors and could easily abuse their employees since the Chicago government effectively banned anyone from opening a competing facility. So instead of the correct response - eliminate government regulation - we got something worse, labor unions.