Why? Both corporations and governments are, in theory, supposed to take actions that maximise benefit to their stakeholders. If those stakeholders decide in the majority that morality is a way in which they seek to derive value from either a corporation or a government then those institutions are presumably bound to deliver on those requirements or to be subsequently punished by the majority or their stakeholders. The fact that shareholders (and customers) seem to be more inclined to be demanding moral behaviours from companies, even though they are also (presumably) citizens, is possibly an indication of the fact companies are more responsive in this regard.

EDIT: autocorrect

Why? This way also works. Good luck changing the govt.

There's nothing wrong with holding a moral lens to all entities, government and private.