Look all I'm saying here is to be objective and cautious. Yes the Bus manual wasn't followed, but at the end of the day its up to the Captain's discretion. For all you know he could have 20 years experience flying An-2s in the Kamchatka area while you were still learning how to tie your shoelaces. Just because you were taught to deice when there is snow on the wings, does not make you correct.
But at the end of the day procedure in the Airbus manual was not followed, as you point you. Just because he is captain doesn't make him king of all decisions. Captain's best interest surely should be safety and not following procedure doesn't spell safety to me. Unless it was an emergency situation, I've never heard of an emergency prompting crew to get airborne asap and skip de-icing.