I’m curious if that article takes into account color calibration? Also, a sample size of 20 is relatively low to make a conclusion.
Anyways, I do think this is an important point: the math of contrast ratios is a model that’s intended to reflect what’s going on with people’s vision; if a large-scale study of people indicates that the white/orange button is easier to read, the math is just wrong: we have to be careful not to force reality into our models, otherwise the modes lose their utility.
The "math" is fine. I'm sure, while it's not perfect, it's suitable in most circumstances. My point remains though is that WCAG are guidelines, not mandates.
The goal always to produce software that is accessable and usable by people, not to satisify a mathematical constraint. WCAG and 'constrast ratios' are a means to that end, but they're not the end goal itself.
Anyways, I do think this is an important point: the math of contrast ratios is a model that’s intended to reflect what’s going on with people’s vision; if a large-scale study of people indicates that the white/orange button is easier to read, the math is just wrong: we have to be careful not to force reality into our models, otherwise the modes lose their utility.