Just show how unheroic Phlox and Archer are this episode, imagine if in the next Superman movie, Superman decides to mirror their actions:
Superman: "Oh no, Brainiac is about blow up Metropolis, perhaps I should stop him! On the other hand, maybe intervention would be wrong, maybe Metropolis is fated to explode today. There are all sorts of social problems in Metropolis, crime, poverty and pollution, perhaps saving them would just make things worse. If I save Metropolis, perhaps one of the people I save will become a serial killer and kill people. Frankly I think it would be imperialistic of me to save Metropolis, so I am just going to let Brainiac blow it up. Bye."