On an iPhone 11 there is about 1cm of vertical space for the content a recurrent reader wants to see: The latest article. Used to be better a couple years ago. Also “From the blog” is not emphasizing that these are actually the most recent articles from the blog and not some random selection
Ok, I'll bite. What's that reason? Because as long as the contrast is there, there is no obvious reason why using that color scheme would lead to less importance or popularity.
Because objective studies have repeatedly shown it's harder to read white text on a black screen, compared to the dark-on-light text that 99.9% of everything else on the planet uses.
It's a way of sending the message, "It's my site, not yours. I don't care if you don't find it legible. Everybody else is wrong, and I'm right."