Few of them stared at brightly glowing dirt, though. And few of them continually stared at dirt a foot or two in front of their faces.

There's debate how much damage that difference causes, but pretending there's no difference is an unhelpful approach.

Tone down your brightness then? I use heavily customized dark themes absolutely everywhere, and my screen is hardly brighter than dirt. I have no problem looking at it for 30+ hours straight (though I don't do this anymore for other reasons.)

Hominids spent 7 million years evolving on that "dirt" they stared at.