Because the internet is for everyone, and it turns out that this content resonated with enough people for them to even upvote it enough to end up on the front page.

Author seems very angry that people are solving a problem in a different what than he’d prefer

Because so many sites insist on shoving dark mode down their readers' throats, despite decades of reliable, repeatable human-interface research that has unequivocally demonstrated that it's the wrong thing to do.

Any other questions, or are you short on time to waste yourself?

Edit due to rate-limiting: It should, but apparently doesn't, go without saying that using a terminal is very different from reading a web page.