OK, since we're going down this road in the other thread, might as well make this abundantly clear.
Since his introduction into wow as this new king figure, Varian was the instigator of this war we are in now. He started the fire, and he fueled the flames that made Garrosh's already obvious anger issues into full blown rage.
Now Garrosh is just as responsible for his own actions. But in any situation, you will always have an instigator. Thrall and Jaina were trying for peace, and yet Varian, who was in the same position as Thrall was, didn't even try, he forced the hordes hand at every turn like an idiot.
This is old news you say? How is this relevant now? Well since people want to keep searching for reasons how and why character go down the path they have, and since people were so adamant to accuse Thrall of making a bad mistake and should be held accountable for it, lets not split hairs.
And even prior to this, when Jaina tried to hold a peace summit in theramore, at the very drop of a hat, when Thrall was trying to make peace with Varian, the second Varian saw Garona, he attacked Thrall, accusing him of backstabbing him, without even listening or trying to. He made first strike, not Thrall, not Garrosh.
So, if you think holding Thrall accountable for Garrosh's actions is right, then either you can acknowledge that Varian is just as responsible for instilling that burning anger and thirst for war on the alliance into Garrosh, and starting all this to begin with.