I think you can read the code. I knowingly made the repo public. You do not even have to login to github. I think it should be ok.

It's just a matter of legalities. Even if you share it openly, it doesn't change its copyright status. Unless you offer a licence or make a statement putting it in the public domain (this doesn't work in all jurisdictions), it remains proprietary.

Of course that doesn't matter too much because you're not going to sue people who use it, but it can still have potentially significant consequences for people who use the code.