This is neither a new, nor profound insight.

Public speaking has been about specious arguments to persuade, bamboozle, and appeal to the crowd instead of to reason with them since its very inception with the Greek Sophists. Some later Roman orators tried to redeem those skills for public service, but it's obvious in the extant manuals on the topic that professional argumentation had only to do with "exchanging of ideas" to lead to an "insight" as an unanticipated side effect.

The author's preconception sounds not just modern, but even a bit naive.