Some times it takes an outsider to see the problems, and I’m not alone in seeing massive democratic problems in China. You don’t know who participated in that poll (and neither do I) was it random people on the street or pro party people? With the amount of surveillance in China, I probably would think twice before speaking against the party.
The communist party has the sole power in China, while other parties technically are legal they haven’t got any power higher than city/regional level.
And then there’s the corruption, they have massive problems with that.
And before you go “hurr durr other countries bad” yes other countries do have problems and some may be worse than China, but that doesn’t legitimise Chinas government.
China also do have a large population of lesser educated people. Not everyone in China are doctors or engineers.