The echo chamber is the defining characteristic of this berserk and entertaining political age: squadrons of foam-flecked absolutists ranting to people who agree with them about everything and thus come to believe that their ludicrous view of the world is shared by everybody.

It is true, for example, of the Stalinist liberal Remainers — that tranche of about one third of the remain vote who will tell you proudly that they have never met anyone who voted leave and that therefore either nobody did vote leave — or they voted leave but we shouldn’t take any notice of them because they...