Despite the routes terminating at China's firewall I don't think it's a good guess to say this was necessarily a Chinese attack. It seems like the interference of the Chinese firewall was simply a side-effect of the new path the network traffic was going. If you were perpetrating this attack it seems more advantageous to re-route the traffic and allow it continue working rather than discoverably interfering with the traffic. Plus if you were going to try to block the route, there's probably a better way of doing it.

China's firewall has a long history of accidental enforcement of censorship outside its jurisdiction, leaked DNS and BGP poison are the most common problem.