I find Jaina's reaction quite understandable. Let's see how many of us remain calm and collected after someone obliterates everyone and everything you've ever cared for.
And I really don't like that our characters have no choice in the matter of aiding the brick-for-brains excuse for a warchief in his wayward plans of worst ideas possible. I don't even LIKE kids and found Garrosh's 'execution' of Audin heinous. The boy was unarmed, you self-serving twat. Go back to that floating rock you spawned from and take your rage out on some clefthoofs instead.