Right. The second issue is that the example grayscale ramps in the page lack a color profile as well, and depending on how you're looking at them (monitor and,

Right. The second issue is that the example grayscale ramps in the page lack a color profile as well, and depending on how you're looking at them (monitor and, sadly, which browser/version) you'll get different results. On my current high-gamut display the uncorrected images look almost linear, while the gamma-corrected ones have too much black (exactly the opposite of what the page is intended to show).