I’ve been both a developer and a development manager (and a few other things), and once upon a time I would have agreed wholeheartedly with this.
Then about 10 years ago I started working with the best PM I have ever known. He is absolutely not technical.
He is, however, a great listener, opionated about protecting people from burnout and dumb processes, honest to a fault, and able to speak candidly and openly to techs, devs, execs, and everything in between, switching language as he goes.
On one project we worked on, I had an advisory role and he ran the development sprints. He was amazing at understanding what the devs needed and managing the manager’s unrealistic expectations of how quickly things could be done.
He also put his foot down and insisted that everything flow through him, to be integrated into schedules based on, well, balancing everything else with business priorities.
It took a some time for the devs to trust him, and it took a lot of soft skill work on his part to gain that trust, but before long they realized their weeks were pretty evenly balanced.
The first big win was no more high priority interrupts from the manager, who had to work through him. That helped a lot.
He knows nothing about development, in the sense of having no idea how to do it.
He does know people and knows how understand what they need.
FWIW, YMMV. He’s a rare breed.