Imagine the Capitol attack in China, it would be a massacre
The difference in behaviour seems more like an "is all you have is a hammer" thing. The fact that China can't decide to randomly bomb Nigeria is a big factor in it not randomly bombing Nigeria and the fact that France could easily bomb Lybia is a big factor in it actually bombing Lybia.
Perhaps you should ask the Uyghurs how their negotiations are going.
Not within China itself, no.
I think it is useful to judge a country, regime etc. by the ways it treats its own citizens when there is any disagreement between them and the government. The power imbalance between an individual citizen and the government lends itself towards abuse quite naturally.
By this standard, the US is not doing exactly great, especially towards certain ethnicities, and many European countries are better off; but China is much, much worse.
If someone wantonly isolates entire cities to stop the spread of Omicron and throws dissenters into prison or "reeducates" Muslims in camps, I don't want them to have any more power on the international scene than they already do. If only because that could inspire other countries and their politicians to behave more like Mr. Xi and his party.
You're way too confident. As a flawed democracy, the US has dropped bombs on 1/3 of the world's population. The US has no morals. The first instinct for the Americans is to bomb. The first instinct for the Chinese is to negotiate.
Also, is the "world" just the US and Europe?