Martin, I agree.  I found more useful info in the second link. The man seemed intent on approaching the question in an organized and repeatable manner.   The Ken Rockwell one..yes, some defects in the argument.

Yikes, we loose info in jpg from using straight "contrast" controls. I am not certain how raw converters handle changes in lights and darks, with or without loss.     I appreciate your thinking and response.   We will see what more is said.        Tom.