The reason an unpopular opinion is held by more than admit it

A rule persists that almost nobody privately supports. Every individual assumes their doubt is unusual, so nobody voices it, so the silence is read by everybody else as agreement. The norm is then enforced with real energy by people who do not believe in it.

What everyone sees

A stable consensus. Public statements line up, nobody objects, and the absence of objection is treated as the strongest available evidence that the consensus is genuine. There is no visible dissent to weigh against it.

What is actually happening

Private belief and public expression can decouple completely. Timur Kuran called the result preference falsification: individuals misrepresent their views under perceived social pressure, and the aggregate misrepresentation then becomes the pressure. Because each person calibrates against what others say rather than what they think, the system is stable while being unsupported — and it can collapse extremely fast once dissent becomes visible, which is why such collapses look sudden and are not.

Why it stays hidden

Because the evidence that would break it is exactly the evidence that is being suppressed. Nobody can observe private belief, and the first person to speak pays the full cost while the second pays almost none. The asymmetry between first and second dissenter is where the whole structure lives.