I agree that inviting contrarianism can be a useful way to communicate (though it probably isn't the best way to present a convincing / 'useful' argument). But

I agree that inviting contrarianism can be a useful way to communicate (though it probably isn't the best way to present a convincing / 'useful' argument). But the medium for many essays lacks an interactive forum. Reactive comments from the audience is only a recent phenomenon. Before the net/web (~1990), the essay lived strictly in a broadcast-style medium. Then, the message had to live or die on its own merits. Careless or provocateur authors risked quick dismissal by an annoyed readership or eventual decline into insignificance. And the degenerate devolved form of contrarians, media trolls, didn't yet exist. Halcyon days they were.