Earlier quoted context omitted.
How would the GPL have prevented this, exactly? More explicitly, how would a license that gives everyone the right to copy, modify and redistribute source code for any purpose without compensation or attribution have prevented Github from building a tool that copies, modifies and redistributes source code without compensation or attribution?
You don't know how the GPL works. The GPL explicitly requires attribution. I don't understand what you thought you were saying. The GPL places strict requirements on the licensing of derivative works. You don't know how the GPL works.
And if they provide attribution?