Suppose your long-term enemy has compromised himself somehow. You're in a position to demand satisfaction, but his position is too strong to actually get rid of him. What could you do instead? In practice, a common solution is to insist that your enemy make a scapegoat of one of his own subordinates.
For example, suppose you have proof that another country committed some atrocity. You know that the order came from the top. But the top isn't going to resign to appease world opinion. So instead, you demand that he hand the general in charge of the atrocity over for a war crimes tribunal.
Seems kind of silly, doesn't it? Since you can't punish the real criminal, you take it out on his flunkie. What's the point?
On reflection, though, there IS a point. What happens when a leader throws an obedient follower to the wolves? It reduces the incentive to follow orders. That makes it harder for the leader to commit further crimes, because his followers have to weigh the costs of disobedience against the costs of being scapegoated. Once the people at the top start giving these bad incentives, moreover, they trickle down throughout the hierarchy.
An interesting history of Russia (this one if memory serves me) argues that this mechanism partly explains the fall of the Soviet Union and subsequent defeats by Chechens and other separatist forces. After some Soviet/Russian generals were scapegoated to placate world opinion, their replacements decided it was safer to ignore criminal orders than to follow them.
We see the same thing in ordinary politics. The President orders a cabinet member to do something. It fails. Since the President isn't going to resign, his critics demand the resignation of the cabinet member. You could object, "What makes you think the replacement will be any better?" But that misses the point. His replacement might not be a better human being, but he's going to be reluctant to follow the kind of orders that turned his predecessor into a sacrificial lamb. And of course, this encourages other ministers to be insubordinate as well.
Bottom line: "I was just following orders" was always a lame excuse. But it turns out that punishing people for following orders has more benefits than meet the eye.