Scrooge's comment is a clue to why he was bitter, "There is nothing the world is so hard on as poverty, and nothing it despises more then trying to attain wealth."

It might be remembered that Scrooge lived in a time when dynasties that did essentially the same thing he did for hundreds of years were admired but individuals like Scrooge despised simply because they the first kind were landowners and the second moneylenders. And the first kind were established and the second not.

Again, that does not condone Scrooge. But condoning was not what he needed, salvation was.

I have heard it said that Scrooge's main vice was wrath rather then avarice. At least that does seem to be the one we ignore. Yet when you look at the movie portrayals of him there does seem to be something to that. He was a bitter old man and when you watch the Ghost of Christmas Past's message you understand that he does have enough to be bitter about. However mentioning that would be defending him; which would in turn imply that the Spirits were coming to judge him when in fact they were coming to help him.