The social credit score (as most Westerners think of it) is a complete myth.
One of the top American experts on Chinese law, at Yale university, calls most Western reporting on the subject "social credit fan fiction."
There are various"social credit" systems in China, but the average person does not interact with them. They mostly exist to regulate businesses.
Individuals in China do not have a social credit score, and basically the only way to actually fall afoul of any social credit system is to break an existing law, and then fail to comply with a court order. Then, you might end up being barred from flying or buying a train ticket. But the idea that there's a number attached to every Chinese person that is constantly going up or down based on how they post online is just complete fiction.
As for "moral relativism," we really should not get into a petty, nationalist match about which country is worse than the other. The US has its own fair share of (arguably way worse) atrocities to answer for (see the entire Middle East over the last 20 years).