Yes, Google, Facebook, Yahoo, Twitter and others will happily collude with the Chinese government, in order to expand their services into that country, if there is money to be made.
On the other hand, if we leave the Chinese people in total isolation, much as what we find in North Korea (it has been estimated that there are fewer IP addresses in use in all of North Korea than in a single city block in NYC - and these are obviously being used by the government and military, not the public), will those people ever come to the realization that their government's propaganda machine is as full of crap as it really is?
I would submit that the downward trends, as reported in the OP's attachment, are as a direct result of reactionary policies of the Chinese government, due to their public's ability, limited as it may be, to reach out through the Great Wall and interact with the rest of the world.
So, while I find the motivations of these companies to be thoroughly reprehensible, at the end of the day, I believe that their actions will eventually prove beneficial. Unfortunately many of these governments are firmly entrenched and significant freedom will likely only come at the expense of much bloodshed and misery for the people.
Sadly, these issues are not limited to China. There are too many other Statist governments, be they some flavor of Marxist, Fascist, Maoist, Socialist, or Theocratic, that take it upon themselves to oppress their people ... for the children. Yes, somehow it is always justified, because it is being done in the best interest of the people.
Of all tyrannies, a tyranny sincerely exercised for the good of its victims may be the most oppressive. It would be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated; but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience.
- C. S. Lewis