In what ways is Oliver Twist a social criticism?

In the aftermath of England's conflict with France, the people who suffered most from economic instability were of course the poor. Overtaxation, inflation, embargo on French imports, and a diminishing food supply were the common citizens' woes. Added to these factors was rising unemployment, as inventions in the manufacturiing sector steadily replaced manuel labour and as war veterans returned home.

The government took drastic measures to discourage the poor's dependence upon state funds.   In 1833, child labor laws were passed, and a year later, the "Poor Laws":

They required that people needing public assistance live in workhouses, where they were poorly fed and badly treated. The object of this plan was to make public assistance unattractive to the poor and thus to decrease the number of people on assistance, as well as the associated costs. The plan did save money, but at a great cost in human suffering, as Dickens makes plain in Oliver Twist.

Ironically, this "welfare" system oppressed the poor more than ever.  It was against such governmental regulation (favoring the interests of the rich rather than those of the poor) that Dickens was primarily speaking out:

In 1822, Dickens's father was transferred back to London, but he had gotten himself deeply in debt by then and was soon sent to a debtors' prison, or workhouse, along with his wife and Dickens's siblings. Dickens, who at twelve was considered old enough to work, had to work in a bootblacking warehouse. Alone in a strange city, separated from his family, he endured harrowing experiences that marked him with a hatred for the social system and the desire to succeed so that he would never have to live this way again.

Dicken's 'legacy of the poor' met a migitated public reception, as people were shocked by the vivid personalized characterization of his anti-heroes. He was accused of "endorsing" the crimes of the desperate and of rationalizing their acts as necessary for survival:

Joseph Gold, in Charles Dickens: Radical Moralist, wrote that it was not surprising that critics in Dickens's day were upset by the book, because what Dickens did was to "humanize the criminal. This was not readily forgiven, for to humanize the criminal is to show his relationship to the reader, who would prefer to regard him as another species." This was very different from previous novels, which either romanticized criminals as gallant outcasts or as complete monsters, utterly inhuman.

Note: The preceding quotes are taken from the references listed below.