In college, for my senior thesis, I wrote a philosophical paper titled "What Would You Have Done: the Role of Empathy in Assessments of Responsibility". As you can likely deduce, I argued that before we make a judgment about someone's moral responsibility for an act, we should try to empathize with the person. In doing so, we acquire more information about their mental state and the context in which performed the action, which can only improve the accuracy of our assessment.
Craig Calcaterra of Hardball Talk made a similar point about players who took performance enhancing drugs:
If you take seriously the ethical and moral choices players made, you have to appreciate the context in which those choices were made. Yes, some players probably sat back and said "hell, I wanna hit more homers." But many more likely felt the pressure to take steroids to save their jobs or solidify their careers with the full knowledge that their clubs would reward the performers and punish the non-performers, with no questions asked about the provenance of that performance whatsoever.
If I understand him correctly, Craig is not trying to absolve these players of their responsibility. Even for those players who felt strong pressure from their ballclubs to take or continue to take steroids, we may still examine their situations and conclude that they are responsible.
But, Craig argues, we cannot simply ignore the "context in which these choices were made." As with any moral judgment, the action itself is not sufficient to make a moral judgment. Not only must we consider the context of the action, but the mental state of the person who committed it.
Do I blame Bonds, McGwire, and the like for taking steroids? Yeah, probably. I do believe that they had a choice, and I believe they made the wrong choice (ethically). However, to simplify the choice to "Should I take steroids or not?" without considering the factors that led to, and influenced, that decision, is rash and unhelpful. There is no correct answer here (well, maybe there is, but we don't know it), and one is perfectly justified in blaming or absolving these players. However, as Craig argues, we must do so with a careful examination of all the factors involved.