While that is one interpretation of how Ares acts that is near at hand, it's not necessarily the only one. And Wilson picks up some more elements.
We have Etta defending the current regime because they have a treaty in place and view them as a guarantoor of stability. There are lots of cases of similar interventions in the post-Second World War era, not all of them involving the USA.
Ares intervening in a latent conflict and breaking it wide open, and then leave when things turns out complex and messy can be interpreted as the USA in Iraq or Afghanistan, but the EU (and allies) in Libya also fits. And on an entirely different level,
Tim Hanley had a very interesting read on Ares:
So what we are seeing here are really personifications on various extreme patterns of behaviour: stability and order above all else from Etta; arm all the oppressed from Ares which is then replaced by justice must be blind and passive (
ie an isolationist stand). With Diana in the middle trying to work out the truth of it all. You can read it as a critique of the USA, but that's mainly because the USA is the most powerful and involved actor in the world in the post-Cold War era. Also note that the USA is hardly isolationist right now, and haven't been since the Second World War. It's a strong current in US the political landscape, though.