It's useful to go back and compare apples to apples when we compare the 19th-century "slum" to the 20th-century slum. You can read Robert Roberts on the Edwardian slum, for instance - a world which he grew up in:
http://www.julielorenzen.net/slum.html
Roberts: However, approximately sixty years after Engels wrote his book, Roberts described the working class as almost being obsessed with cleanliness. A dirty home or even a front step meant lower social status. Roberts wrote “Most people kept what they possessed clean in spite of squalor and ever-invading dirt. Some houses sparkled.”
Or read Riis' How The Other Half Lives:
http://archive.org/details/howotherhalfliv00riisgoog
You can even find an unbiased view of Southern slavery (admittedly milder than Louis XIV's Caribbean version):
http://books.google.com/books/about/A_south_side_view_of_sla...
You won't find anything like:
It never ceased to amaze me how the people could live like that~dirty diapers & sanitary napkins in the hallways, urine & feces everywhere, cockroaches scurrying from one apartment to the other and when you had the unfortunate luck of answering a call on the 11th floor of one of these hell-holes was horrifying! Just going in to see the "moving walls" and the chicken bones on the floor, the stove on for heat even though it was already 140 degrees in there and the stained couches & dirty mattresses on the floor where at least three or four little kids were napping with the roaches! Good times...
Lack of nice material things is one thing. Even in Cabrini-Green they had PlayStations. Louis XIV didn't have no PlayStation. Human degradation is another - and Enlightenment experiments hold the prize. (Especially if you count the "Soviet experiment" to its credit.)