I wouldn’t exactly say he was right since he caused a self fulfilling prophecy.
Mainly the people from Kul Tiras, but from a pure objective standpoint, he was an antagonist during that campaign in WC3: TFT. He launched unprovoked attacks on the Orcs and Darkspear Trolls, the latter of which were not involved in the second war (so he can’t use the ‘revenge’ excuse there). Tried to assassinate Thrall under the guise of a peace treaty meeting (which IRL is a war crime) and stripped Durotar of his natural resources, causing chaos amongst the environment. All of this because of his hatred towards the Orcs who had just helped defeat the Burning Legion at Hyjal. Even Katharine ends up seeing Daelins’ campaign in Kalimdor for what it was when she goes into Thros to find her daughter. He would also do a hostile takeover of Theramore after he found out that Jaina was in the company of ‘horde scum’. Clearly the things I listed is what a heroic character would do…