Well “unprovoked” … provided Blizz whitewashed all the aggressive Alliance moves proceeding that. Or BSed excuses for those acts not to count. The attempted assassination on the Horde’s new Warchief (which was forgot by everyone but a passing mention from Saurfang). The slaughter of Goblin civilians by SI:7 in Silithus (which Blizz tried to invalidated twice. Once with the excuse they originally thought up with Sapphretta. Once because “they’re Goblins lol!” when they realized that the first excuse didn’t chronologically work). Then there was the flooding of Org with so many SI:7 spies civilians were literally tripping over them, to send the deliberate message of “we are always watching”. Which only stoked paranoia. But … they weren’t allowed to count in any capacity, so the Horde attack was unprovoked.
Sigh … its the Varian declaring war on the Horde in WotLK, but Garrosh starting it in both Cata. And then starting it again in MoP. Because of two very conveniently created peace treaties crafted in in between expansion books (just in time for the Horde to break them) … all over again.