Programmer art at it's finest. I think the idea is functionality over presentation though, just look at the sites most GNU projects are hosted on.
I looked at the logos first from a branding and functional perspective and my thought was that like all things there is tremendous variety in the set. Some logos were really good at doing the things you want to do with a brand. Others were metaphorically off-color. Others were really bad.
Again, though, that's normal. Logos are, well, a balancing act between functionality, uniqueness, character, and polish.
If you want more design-inclined people to contribute you'd have to market towards those kinds of people. So it seems like a catch-22.