I think he’s assuming some shared context, namely writing for the purpose of educating or persuading people and aiming for engaging as many people as possible w

I think he’s assuming some shared context, namely writing for the purpose of educating or persuading people and aiming for engaging as many people as possible with the topic at hand. I don’t think he intends his recommendations to apply to people deliberately writing for a much narrower audience (like dense technical or academic literature) or in a particular artistic style or genre.