During the final showdown, Supergirl stops Ruthye from killing Krem (the villain who murdered her family) to save her innocence and spare her the psychological burden of vengeance. As Ruthye runs away from the scene back to the spaceship, Supergirl gleefully stabs Krem repeatedly to death with a sword. In the original "Supergirl: Woman of Tomorrow" comic, Supergirl does not kill Krem but instead banishes him to the Phantom Zone.
"The message" I see in this scene is the hypocrisy of the modern State, which tells people that killing is bad, that you're not strong enough to do it and that you'll hate yourself for it afterward ... and then the State sets a compound full of women and children on fire; or nukes a hospital or a school with a $4m Tomahawk missile, only to launch ANOTHER missile to kill the first responders looking for survivors.
*"Yeah, don't kill your enemies, folks. You're not cut out for it and you'll hate yourself. Suffer your persecutors and every injustice with patience. Vote harder or whatever."*
The fact that Supergirl uses a sword -- a symbol of the State's strength -- to kill the villain further supports this interpretation. Another thing is that the whole "adventure" started because Ruthye wanted vengeance and went looking for someone strong enough to help her. In other words, she went to appeal to the "State" (Supergirl) for justice. Supergirl didn't care about getting justice for Ruthye, but because the villain later happened to poison her dog, THEN she agrees to help find the guy so SHE can get vengeance for her dog.
*... so the dog's life is worth more than the lives of Ruthye's parents?*
Really? Is that the message? It actually echoes something I've said before, which is that nothing changes until our pain becomes their pain. The governor of Mass. only clamped down on drunk drivers after his daughter was killed by one. Congress only banned banks from stacking overdraft fees after a congressman's daughter was forced to pay thousands in stacked overdraft fees. It was only until Supergirl's dog was poisoned that Supergirl gave a damn to stop the gang of marauding terrorists.
They either didn't think through this script or James Gunn really is that much of a piece of shit. Likely both. The whole movie is fucked up and degenerate, but that ending really is that intellectually offensive.
Well, according to my experience, revenge and genocide are amazing. The biggest problem I have with the holocaust is that it's a made up hoax. To be fair, it's comically retarded, but let's replace "holocaust" with an actual genocide of jews. That *should* have happened. At least then we could say "well, you deserved it, don't make us do it again."
Otherwise I have genocided a wasp nest that might have contained ~1000, because one wasp has decided to sting me. Revenge and genocide - and the wasp problem in the entire area vanished since then.
If I'd do the same with brownoids and jews, the euphoria it would cause would last for a lifetime.