I think Marti is right. It is much easier to have moral values when you can afford to. I think that is why middle and upper class both in P &P and in this book can be so judgemental. i believe I do that, today. whe I see someone living in a trailer trash environment, with three kids and under 21, I totally figure it's the girls bad judgement. That is really not fair.
I think Nancy has a maternal feeling for Oliver and though she had to do what she was told by fagin, she regrets it.