I still think it is more complex than you're giving it credit. For example, The Glorious Leader is a bad guy - he's really responsible. And he tells the general's what to do, so they're responsible.
Lets use one of them as an example, say the minister for corrective services. He's responsible for the people tortured and killed in prison camps. Right? He tells the directors of the prisons what to do, so they're responsible. But they may not be the one's who are ordering all the people tortured and killed, so they're less responsible. What about the grounds keepers, janitors, secretaries, guards? Without them the prison might shut down - so they're all responsible. But not as responsible as the prison director. And definitely not as responsible as a general or minister. But they're a bit responsible.
What about the apartment full of people who didn't fight back against the secret police when they were arresting the guy unfairly? Are they responsible?
What about the US - the global hegemon, who could fly planes in an topple the regime? Surely they're the global leadership, so this moral duty would fall to them.
Or China, the dominant regional power?
Or the UN with the UNSC? They sent forces into Iraq claiming the presence of WMDs that didn't exist. Surely they have a responsibility based on precedent to topple North Korea? Are they the global leadership and therefore morally responsible.
Or how about the liberal democratic theory that people have moral equivalence and the right to self determination? That would mean that the leadership is only in power because they let it be. Are the people then responsible and the leaders of the republic?
I think leadership here is a very nebulous concept. Hannah Arendt covered this very well in Eichmann in Jerusalem. These arguments are nothing new. They were the same ones that confronted the Nuremburg trials when they were hanging people. How do you measure how responsible a person is? Where do you draw the 'leadership' line?