I wonder, are/were the attackers terrorists as we understand the term? Lots of people carry out random attacks in China because they're angry and want to take "revenge". They're not actually trying to inflict terror or bring about political change, even if what they do is horrible. It's conceivable they could congregate to carry out attacks together.
There's no point in demanding "action" from the Chinese government if it's not clear who carried out the attack or why.
Well, I don't think this is the right line of thinking. If you have grievances against the Chinese government, don't go around attacking people who probably had no relations to it. There is a word for attacking the defenseless civilian population in hopes of achieving political goals, and I think the word is probably familiar to most people on this board - terrorism.
Also, people with grievances against the government usually acts alone. Take the farmer with the makeshift rocket launcher or the crippled guy who brought explosives to the air port, or even the guy who crashed the plane into the IRS building in '10 here at Austin Texas. Those guys who are fed up with the government due to real or perceived injustice aren't usually stable enough to bring a bunch of their buddies together and launch coordinated assaults.