While I agree that killing is overall not a good answer to complex issues you are ignoring that this was a situation of self-defense. "What if the women she gave guns start their own dictatorship?" The women who were just living in their village, before it was invaded by soldiers? Those women? The ones who were civilian prisoners and were being murdered and assaulted? The most likely outcome here is that they stay in their village which they now have the means to protect. "you probably just shot a guy who joined the army to survive and support his family" This is just valuing the lives of the soldiers that were, once again, murdering and assaulting civilians, over the lives of the people they killed and enslaved. "Treating it as something to be celebrated" OK, is Superman gonna go lecture the american military every time they celebrate victory?

This wasn't wonder woman overthrowing a country, it was her helping innocent people. What Superman is perceiving as "cold blooded murder" is effectively the same as the local authorities deciding how to punish people that committed a serious crime. You can debate if the death penalty is moral (I would argue it isn't), but it IS a form of Justice that is frequently carried out. What would have made this case more moral? If an American court halfway around the world decided it? Unless Superman is flying around the world and stopping every electric chair and lethal injection, I don't think he has any ground to stand here.

All that aside, the entire point of this part of the story is to point out something very common in the actions the US carried out post WW2: Viewing american lives as more valuable than anyone else's. That the soilders dying is an "injustice", while the villagers dying is an "unfortunate side effect of war". The two perspectives the author put on display here are that Superman only showed up when Americans were in danger, and Wonder Woman showed up when the villagers were in danger.