Choosing between parties is arguably less democratic because in many countries with such a system, like the USA, you basically just have corporations/corporate media choosing the candidates, so your "choice" is between corporate candidates, so corporations always win. There is no option to reject the nominee entirely, while in China's system you can reject the nominee. you can just straight up veto candidates.

Westerners often also look at the very end of the process and ignore everything leading up to it. They will say "there's only one candidate on the ballot!" as proof it's undemocratic (even though this happens all the time in the US too...). But this ignores the entire democratic process leading up to how the candidate gets on the ballot in the first place. In Cuba for example, candidates getting on the ballot is a two-year long process resulting from local elections and meetings with mass organizations, but they ignore this entire process and just focus on the final election at the very end.