For consideration, one can pretty objectively determine a programmer who is not qualified. Secretary. CFO. Sysadmin. How would one judge a product manager? That there's no product? That it sucks balls? "We're soliciting feedback and finding product market fit, iterating, A/B testing, we'll be better next quarter, goto 1"

I wouldn't want that job, but I also don't currently know how to bring demonstrable evidence that they're incompetent, either

I have roughly the same opinion about UX folks, but they don't jam up my day to day nearly as much as PMs