Credit where credit's due - a pretty much correct beginners' guide to exposure.

Of course I'm not joking. But all of those are, as I said, side effects of 'ISO'. They are not 'ISO'. They don't have a constant relationship with ISO setting, it varies from camera to camera.
I would argue that lightness very much has a meaning for raw shooters, unless all they ever intend doing with their raw files is store them and maybe analyse them. As soo as you want to display them, lightness has a meaning. But the real point is that ISO is not defined for a raw file, and the effect of the ISO control on a raw file changes from camera to camera.
I'd ask again, if you wish to maintain that this (correct) definition of ISO is erroneous, please do suggest an alternative one which would be accessible to people starting out in photography, and wanting to know what is the function of the ISO control.

ISO is about the relationship between lightness and exposure, not 'brightness'. But ISO is exactly about setting the lightness for a given exposure. Now that's not everything that the ISO control on a camera does.

For sure, who ever said that you shouldn't tell them about how the ISO control operates? But that is not the definition of ISO, it's about what are actually the side -effects - sometimes designed-in side effects. And of course they should be discussed, because they exist and affect practice.

please stop with these derogatory inferences.

That's an argument that you could apply to dismiss any defined measure. The fact that it appears in other theorems 'later' means that it is of importance.

What are we doing when we create a digital representation of a scene? Is that not 'coding'?

I have never said that SNR=1 is a magical threshold, so there is a straw man straight away. However, it is a very commonly affected threshold for DR, so much that commonly, if not otherwise specified, that is the threshold assumed for DR. It is also the threshold that appears in the Shannon-Hartley theorem. So, as the widely accepted and understood threshold, if one's using another, there needs to be some argument as to why that other is more appropriate, which in turn depends on what it is that your metric is trying to achieve. Coming back to Bill's 'PDR' metric, I've never ever seen a clear motivation as to what it's trying to achieve (other than being 'more realistic' in some unstated sense), and nor does the choice of threshold stand up to even cursory examination.

So, I still don't believe that you put forward a coherent argument as to why the things that you called 'errors' are that.

The word 'exposure' has, for more than 100 years, had a firm definition and central place in the theory of photography. The fact that the web has meant a plethora of uniformed so-called 'information' sources by people with zero knowledge about the topic and no editorial control is lamentable, but doesn't affect the meaning of 'exposure' in the theory of photography. In the end, the point is that maybe you can play fast and loose with the terminology in general use, but if you're trying to teach people about a subject, there's an onus on you toi get it right.

I don't disagree. The problem is that Don doesn't have the capacity to understand that Hm (lx･s)[/u] = 0.65BT/F^2 means that scene luminance is one of the determinants of exposure. Neither do all the others that rail against this. Sop the argument simply doesn't work with them.
And it's not just that lack of capacity. See my current discussion with JACS, who is a University teacher of mathematics, so certainly does have that capacity, but is still trying to argue that the ISO definition of ISO is irrelevant to what ISO is.

Yous started off saying it was an error, now you've changed your story, and it's that you don't care whether or not it's correct. I'm not chasing your moving goalpost around any more.