We're talking about a country tha censors a lot more than just the Internet. Reports of propoganda officials following ALL foriegn media reprentitives in China as well as soldiers following people known to disagree with government policy are constant. How do you get reliable information on public opinion in a country where if you disagree with the government, you are gaged by threats, inprisonment or even death. (Could this be why China is the number one place to get spare human parts? Hmmm..have to think on that one).
To get a small understanding of this check out the stuff done in the excellent film, "The Lives of Others". The Chinese Communist Party recruit people at all levels as spies and act quickly when people are discovered who object to Party policy. (Remember this is the country who wrote "The Art of War" which has a large chapter on spies and counter spies) Its impossible to do an accurate poll under such conditions because it will ALWAYS favor the Communist Party. Garbage in garbage out.