I just get tired of the idea that only fiends can be evil.
That's not the idea.
The idea is that the concept of free-willed, sapient creatures conflicts with the concept of moral and ethical nature being pre-determined by species you are. Further, we should not consider creatures "good" or "heroic" if they regularly make value judgements about other free-willed, sapient creatures based solely on their species because that's actually evil. Dehumanizing others through alterity is the foundation of human exploitation and abuse. Why would we want to portray moral and ethical cultures as glorifying or rewarding that behavior?
In practice, what this means is your game will change as follows:
Old version: "You stumble upon a group of orcs. Roll initiative."
New version: "You stumble upon a group of bandits. Roll initiative."
Notice that what you do with the new version is what you already do when you want your PCs to fight a group of
human bandits: you tell them what role they play and not what species they are. That's all you have to do to make it clear that it's those creatures' choice to act they way they are.
It's certainly okay to portray evil cultures or evil organizations. It's fine to have individuals in those cultures or organizations be evil. It's okay for cultures or organizations to be paranoid, bigoted, or xenophobic. However, it's not correct to portray being xenophobic or bigoted as something that a good culture, good organization, or good creature does. Hatred, xenophobia, and bigotry are not Good. It's not even Neutral. It's Evil
. The paranoid, bigoted xenophobes should be the evil ones!
Further, I would argue that it's poor or at least questionable worldbuilding if you make
all members of a given free-willed, sapient race members of an evil culture. It doesn't make sense that all high elves are like X, all dwarves are like Y, all orcs are like A, and all drow are like B. It does make sense that there might be cults or offshoots which are evil (cult of Gruumsh or cult of Lolth) just as what happens with humans, but the idea of race-as-culture is grossly flawed on it's face. It's a crutch.
It's certainly easy to imagine a world where humans are colonizing wilderness land and creating agricultural areas to grow more food, and wilderness cultures -- elves, gnomes, and
orcs -- who may have their own ways of life might come in to conflict with that kind of destruction of their habitation (for lack of a better term). Now you have two groups of people, culturally opposed and causing conflict because of that. You don't need orcs to be evil to have conflict. You don't need orcs to be evil to have open hostility.