The answer is that about everybody makes this determination whether you want them to or not.
Specifically, my question was "who determines which ideas are officially considered 'bad' for purposes of not being institutionally privileged?"
All of us, to some extent, though publishers, administrators, corporate boards, managers, faculty, and editors have much more say. Is there some interesting followup to the obvious here?
Related: Heuristics for Evaluating the Soundness of the Academic Mainstream, Admitting to Bias, The Ideological Turing Test