That entire paragraph is a string of poorly-articultated, cringeworthy sentences. In fact the whole article seems to be a series of strawmen set up on the basis of oddly specific and naive interpretations of management concepts like "servant leadership". There's basically nothing in here that I would agree with as a blanket statement without a lot of company and org-specific provisos.

All that said, to be charitable, I think what the author meant to express is that you don't want to make yourself a bottleneck as a manager, which is a common failure mode for newly converted IC to junior manager. Where he goes off the rails in the most tone-deaf way is describing that as "not doing useful work". As a manager your work is constantly observing what people are doing, staying the hell out of the way when things are working, and leaning in when things are not going well from a team and outcomes perspective. Doing that well is incredibly challenging and important work.

> All that said, to be charitable, I think what the author meant to express is that you don't want to make yourself a bottleneck as a manager,

That's not being charitable, that's just having basic interpretation skills of the very next sentence of the article.