No government can act without the acceptance of a majority of the citizens. China's firewall can only exist because the Chinese people are accepting it in the name of protecting children or other such bullshit - brits should watch out, as their personal liberties have been eroded in the name of safety for too long. And if you live in the US, I suppose you're familiar with the Patriot Act ;-)
No, governments don't do this unless a majority approves - that they approve for the wrong reasons, that's another story entirely. But as I kept saying ever since Snowden's leaks happened - the US government fucked things up, they won't even admit to how badly they fucked up and this will have deep repercussions internationally regarding the future of the Internet. A lot of international (mostly US) companies will get hurt by this, because (1) they didn't have a saying in the matter, yet the public views them as being guilty nonetheless and (2) because of balkanization.
And the US can't point fingers and say "look who's talking", as that won't achieve anything. Say that to the Russian public who approves this. The US, as the stewart of the Internet, should have been careful to not fuck things up so badly in the first place. And after Snowden's leaks I would have liked to see some apologies, some heads falling - but ALAS, no, nothing of the sort - only a direct confirmation that they don't care about the rights of foreign individuals and as a non-US citizen, how do you think that makes me feel?