Morals of scale

Our morals change as the scale changes.  For example as an individual it is immoral to kill, but on a collective scale of a nation it is OK to kill in war or execution.  As the scale increases the moral imperitive becomes more slack.  Now let's go the other way. As an individual it is immoral to kill but if you step on an ant hill you have not done anything immoral ( unless you are a Jainist). But from the point of view of the ants you are a genocidal murderer, a destroyer of worlds.  What obviously seems wrong at one scale becomes mundane at a larger scale.