Note that I was talking about the information bubble
within China, affecting Chinese citizens. The people within it are immune to Chinese government propaganda; the people outside of it (most of the rural population, for starters) are affected by the propaganda.
The Chinese government doesn't care to attempt to change what Americans think about China; they know they won't be able to convince them of anything after so many other sources have already told them this or that thing to believe. So, to Americans, China is a propaganda machine, and China is fine with that. On the other hand, this means Americans never really get to hear what China is telling the Chinese about America, because they don't bother to publish that outside of their borders.
I guess there are three layers to any information bubble, then: at the core, there are informed citizens who both know the propaganda and have facts to reject it; surrounding that, there is a larger group of uninformed propaganda-influenced citizens; and on the outside, there are foreigners, who don't even know what a given country's propaganda says, only that it exists.