I remain convinced that there was some other reason other than cyberforce posturing for the DDOS. Past examples of highly visible international attacks (I'm thinking of SONY here) have been to punish and embarrass companies for being complicit with US foreign propaganda efforts (re leaked Bennett/State Dept./Lynton/RAND emails). I'm not saying the exact same motivation is in play, but as github hosts files - notably code - and many governments have been cracking down on files hosting and shares (like pastebin, etc).
This is speculation, but I prefer the explanation to cyberposturing, since this isn't something China needs to do, and as far as I can tell wouldn't benefit very much from.
The theory is in line with greatfire, as this organization is a "Civil Society Organization" funded ultimately by the US government to spread messages it wants within China. Github is more confusing.