I don’t think anyone has a problem with (well-written, potentially relatable) evil characters, evil races on the other hand are something wildly different that doesn’t belong in fictional settings worthy of the name.
It’s always a matter of culture over nature. Sapient, sentient species are beings of culture, and as such their societies and moral systems are to be understood through culture, not nature. In some very specific cases nature can shape and play a part in culture ; for example, beings like Demons who are infused with Fel and native to the Twisting Nether may have tendencies that reflect the characteristics of Fel and the Twisting Nether (untamed, unpredictable, undefined, prone to disruption as opposed to continuity, etc) ; while beings that were born as Order-aligned constructs may express other natural tendencies, and show an inclination for stability, rationality, organization, etc. Playing with these tendencies is fine and actually it’s a cool tool for worldbuilding cuz it paves the way for a greater variety of perspectives. But those are tendencies. Tendencies that can be challenged, altered and reversed, through history, cultural contact etc. Because sentient species are people, and that’s what people do.
So it’s not about saying the Old Gods and Void Lords shouldn’t be our enemies. By all means, they should mostly be mortal enemies to us, since their vision and their interests contradict ours radically. Think of the Primalists – that Primalist Proto-Dragons want to return Azeroth to a state of elemental chaos doesn’t make them evil : of course they’d want that, such a world better suits them, and they were robbed of that environment by authoritative aliens. It’s understandable. Yet we can’t accept that for obvious reasons and so we fight them.
Same goes for the Void. Being an Old God-offshoot race (Nature) may make you more prone to certain alignments and certain behaviors, which is why most Void-based races we encountered have been hostile to us. But no matter how strong, those are still tendencies ; and we’ve met a race, the Nerubians, for whom these tendencies have been challenged and reversed because they were cut off from the Old Gods long enough for them to envision a new sort of society (Culture).
That way of writing is literally just… it’s objectively better. It makes the setting objectively richer and more engaging.
Well that’s my two cents on it anyway LMAO
From what I recall, the Nerubians in Northrend didn’t all worship Yogg’Saron either; save except a few – but such could be easily said about all our races too (with the Twilight’s Hammer) so jumping back to the present, having some Nerubians side with Xal’atath + the void and then having some fight against them is pretty reasonable.