Well, that's the thing, there is a single party, but this does not mean China is not a democracy. Their government is far more responsive to protests and popular demands, and the Chinese Communist Party is made up from millions of people who get a say from the local level upwards. People are actively involved in designing policy. Contrast this to the US and UK, for instance, where the voices of the general public are drowned out and ignored, and elections are won by appealing to the interests of big businesses and foreign donors. In the UK right now we have a government which is completely beholden to business interests, and a Labour party which has repeatedly purged its socialist elements under the guise of combating anti-semitism. It would be less antagonising if they admitted what they were really all about, which is crushing the working class. We even have a monarchy and state sponsored propaganda to prop them up.