that’s just a number? what objective measures did they use?

Here are the questions they answered and what the scores mean. Here is more information about their methodology if you are curious.

A country that uses the spoiler effect and a two party system to ensure minimal change happens.

I don't like the two-party system either, but the US doesn't "use" the 2-party system to do anything, it just happened organically because of the winner-take all election system. The founding fathers did not anticipate the rise of political parties; its worth remembering how old the US constitution is. There was not a lot of information to go off of.

https://en.wikipedia.org/wiki/Elections_in_China

Elections in China occur under a political system controlled by the Chinese Communist Party (CCP),[1][2][40][41] with all candidate nominations pre-approved by the CCP.[1][10][4][8][42] CCP regulations require members of the People's Congresses, People's Governments, and People's Courts to implement CCP recommendations (including nominations).[43] Elected leaders remain subordinate to the corresponding CCP secretary, and most are appointed by higher-level party organizations.[43]

There are a small number of independent candidates for people's congress, particularly in neighborhoods of major cities, who sometimes campaign using Weibo.[44] Independent candidates are strongly discouraged and face government intervention in their campaigns.[6] In practice, the power of parties other than the CCP is eliminated.[44] Because none of the minor parties have independent bases of support and rely on CCP approval for appointment to positions of power, none have true political power independent of the CCP.[45][46] Whereas there are CCP committees in people's congresses at all levels, none of the other parties operate any form of party parliamentary groups.

The performed elections in China do not meet free and fair election criteria such as ballot access and political media access.

What political beliefs are you actually required to hold to join the CCP? I actually don’t know and the answer to that would be enlightening.

https://en.wikipedia.org/wiki/Organization_of_the_Chinese_Communist_Party#Members

To join the party an applicant must be 18 years of age, and must spend a year as a probationary member.[73] In contrast to the past, when emphasis was placed on the applicants' ideological criteria, the current CCP stresses technical and educational qualifications.[73] However, applicants and members are expected to be both "red and expert".

So it seems like, just to be a member of the CPP you need to at the very least put on a good show of being a communist. That absolutely does not meet the standard of a free election to me.

And I want to make one other thing clear - even if there were zero ideological requirements to join the CCP, there is still a huge difference between 1 party and no parties. With 1 party, you are completely at the mercy of party leadership. If I joined the CCP and make comments critical of, say, President Xi, party officials could simply kick me out of the party, no elections necessary. The same thing could happen if I opposed some policy or if they simply didn't like me.