Maybe they follow the "make it worse, then make it better" approach to user experience.
Even if the end design is objectively worse than the previous/current one, it will feel better compared to the intermediate versions. That might make the users actually complain less in the end.
Comments
It's the first of many iterative design changes coming to Github. It'll all make sense soon enough.
Why not release them when they make sense as a whole?
Maybe they follow the "make it worse, then make it better" approach to user experience.
Even if the end design is objectively worse than the previous/current one, it will feel better compared to the intermediate versions. That might make the users actually complain less in the end.
Agile!