It was a rhetorical question. I knew the answer - it is an excuse because you deem it to be.
As for the rule book, it doesn't attempt to address every one of an almost unlimited number of scenarios that can happen on the field, so asking whether it spells this exact scenario out makes no sense. There is, and always will be some judgement involved, and clearly the rule is that when a player is going to the ground he has to maintain possession all the way through the play.
The officials ruled that he was going to the ground, and that his actions were merely movements taken while in the process of going to the ground, and that he lacked the necessary control for a "football move". If you disagree, so be it, but I think you are way off base to act as if the guys paid to understand and interpret these things at the time had no idea what they were talking about and that you are more qualified to say, AND qualified to say they all covered it up with excuses.