Maybe they do which is why the redemption arcs are so attractive?
Probably. If they can be saved, I can be saved too.
I think this is why the superhero characters have also become less "pure" - the good guys aren't all good, the bad guys aren't all bad - they have to be relatable, rather than the shining example of goodness and evil.
Maybe, though it could also be as simple as I find those types of characters/stories exceedingly boring and statistically it's unlikely that I'm the only one ^_^;