When I was the same age as many of the intended audience of Steven Universe, the lion's share of the cartoons that aired during afternoons were product placement cartoons. The most famous were He-Man, Transformers and G.I. JOE. Rambo and Chuck Norris had animated series during this period. These cartoons in the 1980s had two purpose: to convince young boys to buy action figures and to show an endless struggle against villains that were entirely one note that could only be solved with a never ending cascade of violence.
I have not seen more than a few episodes of Steven Universe, but I have seen many cartoons of that ilk on the Cartoon network. And speaking for myself, I prefer the message in that solutions involving a galactic enemy can be resolved by discussion and calmness rather than just blowing things up. And for the record it is an animated show: unless there has been some radical change in cartoos in the last forty years that I am unaware of, a violent overthrow or any death at all is forbidden by censors. There is no way on earth any animated series for CHILDREN was ever going to end with the kind of resolution that overthrew the facsist regimes throughout history. To quote Garfield and Friends, one of the few self-aware cartoons of the era: "Cartoons can't have blood and gore!" And unless I'm very much mistaken, that's basically how most fascist regimes end. Don't blame the message, blame the medium