Well let's see, if we ignore the fact that evil is subjective...
Orcs: Majority follows Garrosh and Garrosh is backstabbing, mistreating his allies, being a power hungry tyrant. I suppose some might see that as evil, so orcs are mostly evil.
Forsaken: Raise the dead to serve them, can be kinda evil. Otherwise mind their own business and don't care much for the rest. A bit of evil I guess.
Tauren: Tauren? Evil!? Yeah right, not our Tauren.
Trolls: Right now they're not even on the battlefield and their leader is working towards dethroning Garrosh, the biggest "evil" in the Horde. No evil here, unless you think it's evil to destroy a tyrant...?
Blood Elves: Fighting to survive, being treated like complete crap. Nothing evil about wanting to live, and they're not doing anything wrong in doing so but fight a crazy mage chick.
Goblins: Making money on all the war, being greedy as always, thinking about lots of profit. Little evil to some I guess but not really.
Overall: A bit of evil from some races, but otherwise nothing wrong.
Personally the only "evil" I see in the Horde is Garrosh and his followers and I don't even consider them evil, I just hate them because they're traitors to the true ways of the Horde to me.
I'm not even sure I can think of the Mogu and Zandalari and Co. as evil either. One might be doing what he think is right to serve his gods, it's just not in our interests. And the other wants their former glory after losing their home and getting closer to extinction, they're just doing it by trying to take over what's not theirs instead of seeking refuge or something.
Nothing is truly evil, not every being in the entire World of Warcraft consider Sargeras evil, at least I doubt the Legion thinks that... Evil depends on the view point, always will.