I totally read it as "oh, no wonder it 'was never fully published' before now, since the lead investigators were the infamous Ancel Keys and a now-deceased collaborator."
Well also, as pointed out elsewhere, Keys championed reduction in saturated fats, etc. to prevent heart disease. If the results of a trial he conducted disputed that idea, that might have harmed his reputation.
It almost feels like a claim that it is safe to put lead into gasoline.