Other posters have addressed your core question, so I'd like to add something about fault and responsibility. Note, I stole the following example from an article on ethics that was published years ago.
Say I walk into a bar, order a beer, pull out my wallet to pay for it, set my wallet on the counter and drink my beer. A bit later I decide to go to the restroom, but leave my wallet on the counter. When I come back, my wallet is gone. Who's at fault?
The person who took my wallet, of course. No one forced them to steal it. No one put a gun to their head and made them steal. They had a choice and chose to steal. Open and shut - they're at fault.
But...don't I bear some responsibility for what happened? After all, everyone knows you don't leave your wallet unattended in a public place. While I'm not at fault for the wallet being stolen, I did make it possible. So I have to accept responsibility (not fault) when assessing what happened.
Applying this to your example of heroes and villains, the villain is clearly at fault for any heinous acts he commits. But the hero ends up feeling responsible, because the hero's actions made those acts possible. Should the hero feel guilt over this? Probably not (unless, as Umbran points out, he does things so badly he makes the situation worse). But human beings are not rational and we often confuse fault and responsiblity.
In general, I tend to view a situation where I'm at fault as something I need to make amends for. A situation where I'm responsible, on the other hand, is something I need to learn from (so I don't do it again).