It's the idea of a New Sincerity, or post-postmodernism.
Yeah, the world is turning to shit, and nothing matters. So what? What are you doing to make it less shit?
It's the idea that you should be trying to save everyone with the understanding that a small portion are just too far gone to be saved, and you should focus on the ones that you can, because even if you just save one person, that's still a net positive.