Sinclair's Antisentimentalist Novel--How He Does It: A Partial Summing Up

We've all discussed Sinclair's novel The Jungle as anti-sentimentalist in class and how he accomplishes anti-sentimentalism; in brief, I'd like to further examine the "how".
In one instance especially Sinclair uses dehumanization as an anti-sentimentalist device.  Even in the clarity of hindsight, it is still vaguely horrifying.  What he does is liken the factory workers to machines--a disturbing parallel to how the social conscious at the time perceived them.  Sinclair never really relates them to humans--only machines that make machine noise, and animals barely surviving the jungle that is Chicago, that is the work place, that is the meat packing house.  What's more is, the conditions he informs us of are delivered without make-up.  Every blemish is plainly visible and pointed out... with an appeal to reason over all else.  We as the readers are not encouraged to sympathize, rather, we are encouraged to see the horrors as facts.  Sinclair's dehumanization simply contributes to his appeal to reason for very obvious reasons.  Because we have been made to see them as animals, and as machines, it is most probable we will be less likely to sympathize, as we might with another human (who is personified).