That statement displays an invalid assumption (aka "belief") on your part. There's a touch of arrogance in the statement as well.

In my case, I think I understand the concepts fairly well. And I don't teach "everything controls everything." That's not a way to bring a fledgling pilot from the the two-dimensional world of cars to the 3-dimensional world of the air.

I teach one of the two methodologies - the one I personally think makes the most sense as an initial teaching technique to achieve the ultimate goal of coordinated use of pitch and power to control airspeed and vertical rate.

But I'm not arrogant enough to think that mine is the only right way to reach that goal. So I don't argue the issue with zealots.

Compare

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Power setting. Before entering the climb or descent, choose a power setting and estimate the amount of pitch attitude change required to maintain the airspeed.
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with
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Maintain vertical velocity and airspeed. Rate climbs and descents are accomplished by maintaining both a desired vertical velocity and airspeed. They are proficiency maneuvers designed to practice the techniques used during instrument approaches. Pitch attitude controls the desired vertical velocity, and power controls the desired airspeed.
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Both are from the same source. And yes, in one case they are talking about constant rate climbs and descents and in the other constant airspeed climbs and descents. But the bottom line is that the authors of that volume reject a one-size-fits-all approach based on dogma.