Is this April fool joke? Or are you guys really taking this whole Chinese government theory seriously? If you were leading a 1.6bn populated country how much you would care about a programmer's code site?
To give all those conspiracy theorists a clear picture, what really happened is merely the scale of problem you have never worked on or dreamed to be working on outside China.
This happened year ago when a Chinese state funded train ticket booking website accidentally deployed to production with a opensourced Javascript vendor file still linked to github. And first day that site went live, 30 billion visitors tried to secure a ticket for coming Chinese New Year, when took down github for a good while. Yes it was a DDOS attack from China, by train ticket buyers.
Last November, Chinese online c2c marketplace TaoBao.com, saw 16.7bn transactions in one day, with more than 1 billion CNY settled in a minute. If any of the web dev responsible for even a small promotion page left a link of cool jquery plugin from GitHub, you could have written another holy crap evil government attack post here.