"Don't agree with that one" and "Sheesh" are pretty weak counters to detailed, objective arguments based on extensive research and decades of test data.
24 bit is also extremely easy to hear. Arguably more important during the recording phase when headroom is valuable.
Its just as easy to qualify everything with "placebo effect", as it is to be dismissive
If you test this and hear something, it's almost certainly because the ultrasonic signal is being distorted by your amplifier and speakers and you're hearing distortion products that are ending up at frequencies you can hear.
Ideally audio engineers would take the effort to do good 16-bit conversion for distribution, but I realize that's too much to expect of them.