> WHY. WHY DO PEOPLE DO THIS.
Do you like 400 nits of #ffffff right into your eyeballs? No? Me neither.
The alternative is absolute darkness with extremely bright text, which in turn makes it unreadable (if you have astigmatism as I do) and literally causes pain due to the high contrast.
Nothing in nature has such an extreme contrast.
The only reason anyone would ever use full contrast is if they have a shitty 6-bit monitor panel that doesn't even reach the contrast ratio of a shitty 1990's monitor. And they don't even have a proper color profile, so their computer thinks their monitor has all the contrast ratio in the world, and doesn't tonemap fuckall.
The only way to resolve this is if either everyone finally switches on a color managed workflow, or we outright ban the shitty panels where #000000 on #ffffff is necessary for readability instead of being just painful.
#ffffff is the color of looking directly into the sun and absolutely painful bright, #000000 is the color of the deepest, starless night. You need these colors for movies, for games, for images. But your text should never be the contrast between a starless night and looking directly into a star.
Increase the contrast of your monitor, calibrate your panel, but don't build a worse website to compensate for your shitty panel.
EDIT: this comment puts it very well: https://news.ycombinator.com/item?id=26741285