Wow. It looks like they forgot to add one. I'm a bit surprised that GitHub permits creating new public repos without explicitly tagging a license file.
You're surprised that GitHub allows people to host arbitrary repos?! Do you really prefer that GitHub would go "I'm sorry Dave, I'm afraid I can't let you do that"?
"You're under no obligation to choose a license. However, without a license, the default copyright laws apply, meaning that you retain all rights to your source code and no one may reproduce, distribute, or create derivative works from your work."
I have read the quoted GitHub docs page before and also found it somewhat odd. Not because it shouldn't be allowed to post public code without a LICENSE (or with a restrictive one), but because GitHub has a "Fork" button on every repository. It's strange to me that GitHub has a one-click button that can violate the default terms of code uploaded to the site.
Because that use case feels pretty far from the typical one for a public GitHub repo. Even when it was intended, having reliable metadata indicating that fact would be nice.
Absolutely agreed, but there's a vast difference between "would be nice" and "should require". I for one strongly prefer to avoid putting up any additional barriers to sharing, even at the cost of the default value being all rights reserved (which is a sensible default).
This is similar to saying that posting code anywhere online is useless. Not everyone is trying to start a collaborative project. Sometimes people just use github to showcase code, because it's a convenient platform.