The entire "Steven Universe" and "Bismuth" tags are full of salt. Get some popcorn for it.
Writing aside time!
I have not seen the show at all, but a friend of mine was discussing what happened. This friend loathes Tumblr and did have a point about the whole thing when discussing the show's handling of the topic of war. People kill each other in war. There is no way of getting around that fact, because it isn't war otherwise by definition. I agree with some of the sentiment she has, since a big problem in stories that try to have an anti-violence message while the main characters are active participants in a war, ignores that they actively chose to be involved and maintain involvement in said war, and that it is a
war they are in instead of a heated political disagreement.
Incidentally, I just Googled the topic in relation to Steven Universe and the other side in the show are apparently genocidal maniacs who would literally kill everything on Earth. So, to keep with the fictional examples, it'd be like the Rebel Alliance in Star Wars going "Fuck it, let's let the Empire murder entire planets with the Death Star, because a few of us are squeamish about killing anyone whatsoever." Such a character essentially cares more about their sentimentality than the lives of countless innocent people. This is rarely addressed in such stories when it comes up, though, because then that makes the writer's anti-war message fall flat.
However, much of Tumblr doesn't see it like that. They just want to use it as an excuse, to say that they deserve to treat people who had nothing to do with a crime centuries ago are guilty by some random demographic trait. They don't care about the idea of the other side being genocidal in the series at all, since they think genocide is a
grand idea, if all their "kill all white people," "kill all men," etc. posts are anything to go by.