PM has to be nontechnical so they can manage the symptoms. PM also has to be technical to not trigger the worst of
Or, they can simply be better at management.
The head of a space program doesn't need to be an astronaut. An admiral doesn't have to know how to swim. A PM doesn't have to know all the various engineering disciplines the project may touch.
The comment was derisive, and therefore poor leadership. Period.
Ah and there's the rub. A PM in a software project should not be a non-technical person (because tbh what's even the point, how would a 'non-technical' person even be able to evaluate technical decisions and their implementation?)
Would you fly in a plane, or drive over a bridge that was built under supervision of a 'non-technical' PM?