FWIW, my personal experience says differently. I recently got back from a few months in China, and while I was there I had a conversation with a young man who was 100% convinced Tiananmen Square was a rumor started by anti government 'bad guys'.
I just got back from a few months in China. These services are definitely blocked through DPI. It's frustrating. It's also interesting what happens to your mind when you can't read what you'd like to, talk about what you'd like to, and revert the accepted status quo for everything.