Speed of sound:
I don't buy this.
You are not flying into a black hole if visibility is 10nm, you are below the scattered cloud and you can see eight bright red lights in front of you.
PAPIs either work or they don't. They are either on or off and they don't change angle once they are installed and certified. Even if I was Albert Einstein I would trust eight red lights over my calculations.
There is a very good reason why 'too low' is red and 'too high' is white.
PAPIs and VASIs have been found on occasion to be badly misaligned. In fact, for purposes of the visual segment (as defined in TERPs, Chapter 2) the FAA presumes such lights are unreliable for purposes of the visual segment of a NPA. (That presumption can be overcome on a case by case basis.) At an airport such as BHM I presume the FAA had verified these PAPIs as being correctly aligned. Otherwise, the two approaches would have categorically been NA at night because the visual segment is encumbered by penetrations of a 34:1 slope in the visual segment and, perhaps even a 20:1 slope (higher terrain a bit left of centerline with lots of trees and homes.
But, for all we know at this point the flight may have been cleared for a visual.