it comes down to stakes.
Would you actually enjoy a story where the Villains goal was the extermination of "Insert Nice People Here"?
On the other hand, there's a book I read a LOOOOOONG time ago... like, a decade ago, called "Xenocides", it involved multiple species but the race that got set up to be the bad guys(due to being the titular Xenocides) turned out to not be bad guys.
Basically, Humanity meets Space Doggos(an artificial race genetically required to have... masters isn't quite the right word... partners they listen to alot? I dunno, the relationship is pretty hard to pin down), Space Doggos have been looking for ...partners... for a long ass time and for a bit thought about maybe the Xenocides but then they got nukes and at the first opportunity blew up the neighboring, sapient life-bearing, planet. This, understandably, turned them off.
Then a human crew and some Xenocides wind up on said neighboring planet after we've seen a bunch from both sides. AAAAND it turns out there was a heck of a lot more to the story than what Space Doggos saw. Xenocides you see, had these cyclic wars, they weren't over resources or personal disagreements, or frankly, as far as they could tell, anything at all. The entire planet would break into absurdly destructive wars periodically. As it turns out, precisely when said neighbouring planet got closest. So, since if that happens while they have nukes that's a PROBLEM, they nuke the planet "causing" the problems. If it doesn't work, hey, no nukes on world while we kill each other with all our other tools.
As it turns out that "Sapient Race" on said neighboring planet literally eats, like... I'm not quite sure what but some sort of, Impulse Control maybe? Whatever combination of factors lets a species maintain a society? It's said they eat "Sapience" in the book itself buuuuuuut. The Xenocides have this organ that basically stores an edible memory copy, they use the organ to convey certain things. Before the Xenocides and Humans manage to get away from the arena the Neighbors use to eat the Xenocides Sapience while they are there a bunch of said "edible memories" winds up in the hands of said Neighbors and the book closes on the only Neighbor we ever get any thoughts from going "OOOOOOOOOOOOH, this works".
So like, who are the villains? Who won? I have no idea but that book left a mark. I rarely read a book once and can then summarize it this well a decade later.
EDIT: FOUND IT! I misremembered the title!
Background to The Xenocide Mission | Ben Jeapes
EDIT2: Holy hell it's part of a series... I need this series...