Varian’s character makes perfect sense though. He hates Orcs and anything associated with them because every experience he’s had with them up the end of Wrath is terrible.
They sacked his city when he was a child. They killed close friends and allies. And when he comes back to his crown, after having spent a decent amount of time as a gladiator-slave to an orc, he finds that the Alliance has essentially been in a prolonged cold war with the Horde. He heads up north, and who’s the Horde’s primary military leader in Northrend? Garrosh Hellscream, who’s currently on a massive ego trip from learning that his dad wasn’t a complete waste of space, and raring for a fight with the Alliance.
And even so, Varian holds himself back, because despite the evidence of his eyes, ears and past experiences, his advisors are telling him that there’s more to the Horde. That he’s wrong. So he does. Oh, he gripes and snipes, but he doesn’t resort to his instinct, which is to attack.
Until Wrathgate. Where, to his mind, the worst suspicions of the Horde are proven true. So he attacks. The wolf is loose and even at the gates of Icecrown, the Horde and the Alliance are at war and they fought all the way up, right till Saurfang Junior.
When Varok came for his son, that was a huge moment for Varian, because he empathises both as a man who loved his son more than anything else, and as the wolf (who at this point was still a decent part of his personality) who saw the pack above all else. That simple empathy was the kickstart for all his character development, because it was impossible for him to completely reconcile the idea of a mindless, bloodthirsty Horde with the image of a grieving father.
Varian, and his contrasts with Garrosh, were actually some of Blizzard’s best writing in my opinion.
