The US does track what you say on Facebook to see how much of a terrorist or criminal you might be. Just because you think "praise the government" isn't worthy of reward, doesn't mean it isn't. Afterall, China doesn't have a democracy, so if people are too dissatisfied with the government, instead of voting it out, they might have a revolution, which would be disastrous. In that environment, praising the government can be helpful to keep people safe from violence.