Earlier quoted context omitted.
The Github ToS gives users the right to fork any public repos.
So someone steals my source code and posts it on GitHub, now i no longer have copyright rights? The duty is on the copier to ensure they are granted a license.
It's not just a duty of copier to ensure they are granted a license. Legal stuff is never clear cut, but if someone agreed to TOS, it should be generally (that's a funny word that can mean anything) safe to assume that s/he does abide by it.
In this case, there is an obvious conflict and when there are two conflicting clasuses... that's fun for laywers.