TBF the idea that any and all fingerprinting falls under the umbrella of exploiting a vulnerability was also presented as an assertion. At least personally I think it's a rather absurd notion.

Certainly you can exploit what I would consider a vulnerability to obtain information useful for fingerprinting. But you can also assemble readily available information and I don't think that doing so is an exploit though in most cases it probably qualifies as an unfortunate oversight on the part of the software developer.

1) wanting functionality that isn't provided and working around that

and

2) restoring such functionality in the face of countermeasures

The absence of functionality isn't a clear signal of intent, while countermeasures against said functionality is.

And then there is the distinction between the intent of the software publisher and the intent of the user. There is a big ethical difference between "Mozilla doesn't want advertisers tracking their users" and "those users don't want to be tracked". If these guys want to draw the line at "if there is a signal from the user that they want privacy, we won't track them", I think that's reasonable.