Probably at least twenty years ago I read a short story in which people had become way too divided over ethnic/gender/social/orientation issues. It got to the point where civil war started over left or right handedness, or the color of your eyes. People couldn’t band together at all because they weren’t just alike.
At the end of the story two tired survivors are ready to give up the struggle, when they are confronted by a woman who gives them little self immolation kits, reminding them “We haven’t won the war against ourselves” or something like that. The last line of the story mentions the two guys looking out into the darkness and seeing all these little fires, all over the place.
I’ve tried Googling, honest I have, but haven’t come up with a title or story that fits. Can the teeming millions help?