It's not even the "quality of the project" like suggested in this thread. It's the quality of the commit messages (meta-data, documentation)

That's like someone who paints for a hobby, and shows their paints off on the internet, and people would post stuff like "Well cool painting, but you didn't really explain what kind of paint you've used, who your inspirations were" etc etc

When I'm building Open Source stuff as a hobby for things that are useful to me, and also dump them on Github - because it's a good backup system - I don't really care whether people might go through the commit history as means to figure out how I've build it