This feedback has been helpful for me too; I incorporated the discussion around the Helmholtz–Kohlrausch effect into the “contrast is complex” section of my web best practices article.
I think the Helmholtz-Kohlrausch effect also ties into my concerns regarding overstimulation, also described in the same section of that article. Over-saturation of perceptually “light” colors that also look like “warning” colors (e.g. yellow, which contains the perceptually-bright green along with red) can be psychologically stressful.
I’m beginning to think that a single scalar value might not be the best way to represent all these different axes. Designers should try to strike different balances between different sets of values, depending on responses to media queries.
On the other hand, the “default” values should still try to “even-out” potential harms and conform to existing norms, because fingerprinting-averse users (and users who just need to borrow someone else’s un-personalized machine) should still receive some accommodation.