That's not a skill test, or you'd point to the "test" instead of telling me to interview for a job role. That's a skilled judgement.

It is a generalization, but it's not unfair. That's the mistake you're making. Is it "unfair" to call the British people Roast Beef, or calling French people Froggies. Those are generalizations but are fair (or were at least). British people genuinely eat a disproportionate amount of Roast Beef and French people genuinely eat Frogs legs.

And there are genuinely more bad PMs than good ones and lots of developers have experience "managing" their PM and trying to ensure they don't do too much harm, like the GP that started this discussion.

Don't worry, most engineers will quickly realize when a PM is good and let them do their job without "managing" them. In fact, it's a delight working with one as they do genuinely make the dev process so much better.