The JavaScript used is very amateurish with many outmoded features, poorly optimized. I couldn't believe they were loading jquery, for example. This looks to be the work of a script kiddie rather then a superpower's cyber warriors.
I agree - but it might just be deflection. The Chinese could use the same argument to assert they bore no responsibility. Besides - everybody has jquery cached. Why create an ajax from scratch and add to the weight of the crap they are injecting into the script?
For quick and dirty I like it. Its not exactly long term or really destructive - but its kind of a cute and clever attack.
Github's response to pop an alert was priceless. Sure it probably annoyed the hell out of millions of Chinese people - and their government will probably claim Github attacked them --- but the truth will out... maybe.