Simple: I have grown rather tired of the color scheme over the years, and it's become ancient. To the best of my knowledge, users still have the ability to make a web page appear in whatever colors they want. That job gets hard if I try to fight with them, so I've removed all the color-altering junk from the stylesheet.

Not-so-simple answer: I usually detest white backgrounds. That was the whole impetus for my having a scheme that was significantly darker. But I ended up falling into a rabbit hole which was connected to some labyrinth, where now I'd have to literally fight with everything (and possibly, everyone) to get a color scheme that looked decent. I've had it with this game after so many years.

I'm no web designer. I'm not required to make things "pop." I'm not famous, or significant, or remotely unique. Usually, I just want to convey a small amount of information.

Therefore, I believe I should leave the color scheme of this part of the web at its default, and put the choice (if it still exists) back in the user's hands.

... and it enables me to be lazier than I have been.