Only GPS provides absolute altitude. Altitude based on barometric pressure proves Nietzsche was correct.
If absolute altitude was required then perhaps you might have a point, although one could make an argument about the use of a RadAlt and what your term "absolute altitude" defines.
Yet this rabbit hole can be avoided because all that was reflected was around the term "downhill" and that in the context of flying etc etc the altimeter suggesting its value is reducing might be good enough.
I hadn't seen the car crash of the other post Vance and I am less aware of what generated such out pouring. Hey Ho. It might be regrettable in terms of its language although and I'll put my head above the wall to say this I have a ounce of sympathy for the frustration. I don't think I could work with you but then many people can't work with me.