I'm talking about Naruto's justification for chasing after Sasuke not about Orochimaru. Once Sasuke defeated Orochimaru and still didn't return to the village. Naruto lost any justification for chasing after Sasuke other then he wants to.
Oh I agree though I say he lost any justification after the valley of the end fight at the end of part after he put a hole in his chest and broke his neck and back. I hate how people say sasuke was a victim and was brainwashed into doing what he did and that's not right he knew full well what he was doing and it was of his own free will so really sasuke is not a vitcim I'd say obito was more of a victim.