Except there’s two flashbacks that contradict this "no life was harmed in the making of this empire" nonsense. One in which Yellow is giving explicit orders to eradicate all the organic (with Yellows responses implying that her forces are dealing with some sort of organized resistance that would indicate intelligence) and another where Pink brought organic life from a planet that was destroyed. And even then, it’s pretty clear that the Diamonds don‘t make any distinction between different types of organic life, so any intelligent species would get the same treatment.
I’m sure Ian would backpedal and say that, sure, the Diamonds destroyed planets that had some clearly sentient life, but that’s not intelligent life so it’s totally different, with absolutely no sense of irony. Nevermind that same logic was used to justify many genocides, but by this same logic humans shouldn’t try to preserve endangered species either. SU being pro-animal abuse confirmed I guess.
They also don’t seem to understand that the reason people don’t accept the Diamonds being redeemed (or "redeemed" even though there’s no indication in-show that we’re meant to see the Diamonds as anything other than quirky aunts who just made a few mistakes) is because they treat everything they did so dismissively. First they show shattering as being the worst thing that can happen to a Gem, and were telling completely okay with people calling the Franken-Fusions a rape metaphor when it got them praise, but now that people are going "hey you know maybe the planet-destroying tyrants just bumming around and hand-waving all the messed up shit they did in the name of control isn’t a satisfying conclusion" is being met with " they step in with this "OMG stop being so edgy! We showed that they can reverse literally everything they did to free them from all consequences in a throwaway scene, that should be enough! Besides we told you they aren’t really redeemed anyways!"
Sometimes I do seriously wonder what sort of skeletons are lurking in their closets that they get this defensive when people point out that their already clunky "everyone deserves a second chance uwu" gets really muddled when you decide to include planet-wide destruction and horrific inhumane experimentation into the mix.