Insofar as one may see the crimes at Abu Ghraib as low-level soldiers taking advantage of insufficient oversight to commit abuses, then I suppose Rumsfeld took responsibility. If, however, one sees the abuse at Abu Ghraib as the manifestation of a culture (if not direct instruction, which I don't rule out at all) of torture, he hasn't taken sufficient responsibility. I honestly don't know which one it really is, and may never know since government does not have the balls to investigate and disclose it (Obama included). But, my feeling is that someone at the top started the mess and walked away free. Of course, releasing the photos would bring us no closer to justice on individuals. But, I do think it would bring us closer to justice insofar as America is responsible for those crimes. Not that the country would be punished, but the crimes would be proclaimed and repented of.
You know Obama is pissed that he has to cover up for a corrupt and incompetent administration. At least he puts his country first.
I can also buy the argument that our torture policy made abuse easier in these prisons. but I don't know if you could make that case in a court room.