How much blame can you assign to WWII Nazis, and where is the line drawn between personal maliciousness and cooperation in order to not be persecuted?

I noticed this article on BBC news this morning: http://news.bbc.co.uk/2/hi/europe/8364447.stm

It concerns a 90 year old German SS officer and a charge of murdering 58 Jews during his service in World War II. Right away, I thought, “He deserves it for killing all those people”, but then I got to thinking…

If he didn’t obey his commanding officer, there is no doubt that he would have been shot by firing line or worse. How much blame can one cast on a person who has done “evil” things under the vastly intimidating command of another?

I don’t mean to argue that he should be forgiven since he was commanded to do so, I’m just trying to see how other people feel about this.