The idea is that you can write your blog posts in your favorite coding editor instead of some web form. Some people find that easier - I certainly feel more at home in my editor.
The real reason it's "for hackers" is for marketing. That and improving its chances for a front-page mention here.
If it said "a blogging framework for writers" do you think it would even get mentioned at hackernews?
It seems like YABF, with the possible exception of pretty good support for code display.
Other threads here say it's basically Jekyll. I did some searches. It's not Jekyll. Jekyll has zero branding, it's just a github project.
Good taglines define a brand. This one's a good tagline. Good enough to get the front page here.
What's so hard about using your own editor and when you're done, pasting your text in the web form?