You can extend that to any point of the chain, salespeople can be considered as just neutral and tool like as programmers and the blame shifted up ad infinitum.
While I don't think that he was complicit in this case (maybe the thought that what he was doing could have bad repercussions never went through his head, I don't know...), if you know that you're writing a program that will be used to calculate a way to kill the biggest number of people in a terrorist attack, would you still claim that you're not complicit because your boss that is paying you are the one complicit?
If you don't know what are the uses of the program, I think that you can claim that, but if you know, definitely you're being complicit, even if you're being paid or working under orders (and not under duress).