You didn't say his concerns were valid. You said you thought he was not "wholly wrong". Regardless, Plato being a crank about writing proves only that cranks existed before writing. It does nothing to help you interrogate nor help set you down the path to interrogate the problems mentioned (which is why I categorized it as a thought terminating cliche).
Your referenced article is basically a long-form version of your post, which has a perceivable bias toward the viewpoint that every newly-introduced technology can or will inevitably result in "progress" for humanity as a whole regardless of the methods of implementation or the incentives in the technology itself.
Far from being an instance of skub (https://pbfcomics.com/comics/skub/) as trumpeting this perspective -- perhaps unknowingly -- implies that it is (i.e. an agnostic technology / inanimate object that "two sides" are getting emotionally charged about), LLMs (and their "agentic" offspring) are both deliberately and unwittingly programmed to be biased. There are real concerns about this particular set of technologies that posting a quote from an ancient tome does not dismiss.