AquaMilotic
yay
If it was cheating they wouldn't have put it in the game. Using EVed Pokémon against someone who does not EV train is unfair, but it is not cheating.
How is using EVed Pokemon against non-EV-trainers unfair? If they choose to not EV train, why shouldn't I? Why should that restrict me from EV training? It's their choise to not EV train, and my choice to EV train.
I've been called cheater by my cousin regulary, because my own bred and EV trained non-legendary Pokemon are much stronger than his hacked legendary Pokemon he caught at Lv.100, I know how it feels. I tried to explain him how EV training works, but he doesn't listen and calls me a cheater (while he cheats by getting hacked Pokemon, I take time for and put effort into raising Pokemon).
Everything that is possible within the limits of the game (except for glitches) is legal and isn't cheating. If you bypass the boundaries of the game, for example by hacking, it is cheating.