But the author of that page is not concerned with readability or accessibility. He just wants things to look cool and design-y. One piece of supporting evidence he cites is some random photo he took that doesn't contain #000000 black. That doesn't mean anything, it could be that it's over-exposed, or has poor contrast, or had some silly filter applied. This leads me to think that the author of that page doesn't know what he's talking about.
So you routinely encounter photographs that have noticable areas where sensor did not receive any light during exposure? To the point where you feel not having completely unlit parts of a photo is a sign of over-exposure or filters? Are you an astrophotographer?
Wow, I was searching for this exact link for more than a decade (!). I remember seeing it on HN when I was new here and couldn't find the article ever again. Thanks for sharing!