To interfere with foreign citizens' probing of their network?
I tried pinging dropbox.com from the justping site and for China they have
Shanghai, China: Packets lost (100%)
Looks like good data, no conspiracies.
I tried this as well. The first time Shanghai, China gave 100% packet loss for dropbox.com but every subsequent time I have tried all packets have been delivered.
Pinging facebook.com seems to drop all packets reliably though.