Bill:
Seems to me that the title "A Repulsive Suggestion" on a discussion thread is a sure way to preload the discussion with polarizing intent. Not a good choice of a thread title, IMO, if you're looking for an objective discussion.
As Oren intimated, using the results of a particular camera's JPEG processing engine as a guide to raw exposure is not necessarily the best way to learn proper exposure for raw files because raw files and JPEG files represent two very different environments for the captured data, with different intents expressed. Raw files are image data intended to be rendered to a finished form; JPEGs are intended to be a image in finished form scaled to a quality spec for a particular destination display medium. What works for one with regard to exposure is not necessarily optimal for the other.
I can't say that I've observed the 'degradation' of quality between raw and JPEG outputs that Chris mentions, and certainly not across all the different brands and models of digital cameras I've owned and used. But then I only rarely judge photos by the maximum resolution or tonal capabilities of the equipment I make them with and even less frequently do I print things to sizes at the limits of the spec for that equipment.
Some of the diverse equipment I've owned and used was only capable of JPEG output, others were only capable of raw output, most could do both. I've gotten some satisfying (and very saleable, exhibitable) photographs from all of it. What that takes is understanding the particular camera, what it does, and how to get what you want from it.
I use Lightroom Classic too, which means that the actual editing workflow from raw files is pretty similar to what you have with JPEGs, and that what you can see if you are skilled is that you have fewer degrees of freedom with JPEGs.
Practice with a given camera setup, and experimentation in different lighting situations for what over- and under-exposure nets you for various types of scenes and lighting, is surely much more important than debating whether raw or JPEG should be used... to me at least. 😀
G