The moral of the story of Lot, though, is how city life, living amongst the ungodly, influences a person toward evil tendencies.
That's certainly one way of interpreting it, but I don't see it that way at all and I don't think a close reading of the text supports it. After all, Lot lived among them and considered himself part of the community. (He calls the Sodomites brothers in Genesis 19:6-8.)
The way I read it, the story is more about God's ability and willingness to rescue the righteous from bad situations -- in particular here, getting mixed up with a bad crowd.
I found a very detailed interpretation of this
here.
