Github Terms state: "You may not use the Service for any illegal or unauthorized purpose. You must not, in the use of the Service, violate any laws in your jurisdiction (including but not limited to copyright or trademark laws)."

which seems a bit wishy washy. The use of Github to host code doesn't seem to be violating any laws. The execution of the code does however. Splitting hairs no doubt, but it doesn't seem that merely hosting code that facilities copyright infringement is in itself copyright infringement. Granted if Github wants to uphold DMCA Safe Harbor they need to respond right away.