I like the link to Nagel's "Moral Luck." I too think that like Nagel said, if we remove responsibility from morality then morality no longer exists. That is, we can't allow moral luck to remove responsibility from our lives. Moral luck only plays a part. Another large part is intention, which is a major point brought out in this article. The author points out the importance in the intentions of our actions. Accidentally stepping on someone's foot is much different than purposefully stomping on someone's foot. Yet, either way, you are doing the exact same action. So why is there a difference? If we removed intention then there would not be a difference, you would simply be stepping on someone's foot. But when you factor in intention, I think morality is back in the equation. You certainly would not be mad at someone for accidentally stepping on your foot (or probably not mad), but if they purposefully stomped on your foot, you might get a little angry. Thus, you are responsible for your intentions, which allow us to feel resentment, blame, guilt, etc.
It is important to recognize that reactive attitudes are critical in regarding other beings as beings that also possess moral agency. But it is also important to recognize that there are some beings who do not deserve said reactive attitudes because they lack moral agency for whatever reason. For example, though one might harbor resentment toward someone who punched her in the face with the intention of causing her harm, it would not be fair to harbor resentment toward someone who has some physical impairment that prevents him from controlling his bodily movements. In this sense, that being lacks the agency to control whether or not they injure someone else and should not be resented for it, as it is something beyond his control. Recognizing this distinction allows us to have empathy for those whose agency allows them to be seen as existing within the bounds of the moral sphere as well as for those who cannot be a part of it for reasons beyond their control.