Oh, I'm sorry, I thought this was a discussion about acknowledging the death and harm caused by capitalism. Is that not what this discussion was about? Why are you suddenly changing the subject? Let's roll with it, then.

Average quality of life in every imaginable facet has improved over the last century in almost every country, China just had a lower starting point before catching up to the modern world, most of which was done between the 70s and 90s. One growing problem in China is Homelessness as rural and migrant workers numbering in the hundreds of millions are ineligible for housing in the cities they work in because their Hukou designation is elsewhere. China has 814 Billionaires if you include Hong Kong and Macau. Just like the USA and Europe they have rising youth unemployment and constant banking crisis.

Historically, why is it that most (if not all) human rights declarations happened in slave-owning and/or imperialist countries?

This statement shows a severe lack of historical awareness about eastern nations including China. By the pound, there has been more bloodshed over class disputes there than any other corner of the earth.