I'm not trying to be mean, but I don't think he has any case for promotion under those circumstances.
Yes, I'm aware it looks like the committee was staffed with "idiots", that is, people whose expertise was necessary for the committee to function but wasn't technical. His job was to provide the technical expertise, and to make the committee aware of the technical implications of what they were deciding upon.
He failed. Maybe it was because they really were idiots. More likely, he didn't have the political, persuasive, and perhaps even conversational skills necessary to persuade a group of non-technical people what the implications were of what they were asking for.
Either way, the committee made recommendations his job was to prevent.
Now the purpose of a promotion is to put you in a position where your political skills can be used more directly to steer the direction of an organization. If someone has poor political skills, they're going to botch that job, and their organization will be hampered, not helped, by their promotion.
As nerds we tend to be a little technocratic in our viewpoint and think that organizational structures work with the most knowledgable person at the top. They don't. What matters is that as people rise within an organization, their skills tend towards listening, delegating, and communicating difficult ideas. We're seen at least one case recently where geeks went in a rage because someone with zero skills in those areas got promoted, and then kicked out, because a particular incident that required their skills to be top notch was completely botched. The tech community refused to believe that and decided it was because the person had disagreeable opinions instead.
But that's the way the world works. And promotions need to be given to people suited for particular roles in an organization, not as rewards because you were vindicated after the fact, rather than able to convince people to stop a disaster from occuring to begin with.