1. Because of their market pivot, which was to avoid having the whole project get destabilized and destroyed. Their stated intention is to become a socialist country. I don’t think it’s worth thinking about it in terms of trust unless you’re a Chinese citizen. Worst case they don’t pivot and the world is just completely fucked.
2. There’s child labor of course, but that’s just a feature of capitalism.
3. None of my fiance’s family has ever interacted with any kind of social credit system, it’s apparently mainly for business entities.
4. Certainly nothing like what’s been reported breathlessly in Western media.

Re 4.) - Here’s the UN’s report on Xinjiang. It’s the closest thing to an unbiased report you’re going to get.

https://www.ohchr.org/sites/default/files/documents/countries/2022-08-31/22-08-31-final-assesment.pdf

Pretty much everything else that’s not from the Chinese government is various degrees of creative bullshit. The Chinese government’s obviously got a bias and an agenda. If you want any kind of idea what’s “really” going on (was going on, apparently they wrapped up their counter-terrorism operation a year or two back) this is probably the best resource available.

1. China itself doesn’t even claim it is in a preliminary stage of socialism yet and it is easy to misunderstand the decisions they have made and the socialist character of their government if the depiction of Marxism you have been given is simplistic and idealist, which is typically the case in countries like the US where Marxism is intentionally misrepresented to people through the media and in schools (including most higher ed). China is a socialist state, in that it has a communist party in political control (and despite what some say the CPC has maintained a working-class character and it is not controlled by capitalists) but it has not achieved socialist development by their own estimate, although they plan on achieving it by 2050.

At its core, Marxism isn’t simply a critique of capitalism (although this is an essential component of Marxism, no doubt) but what enabled Marx to give such a (nearly) complete understanding of the political-economy of capitalism and develop so many core socialist principles was his application of a logical tool, a system of reasoning to help understand social change. Marx was a materialist, believing that current conditions can be understood by studying the world as it is and evaluating its history. He used the hegelian concept of the dialectic to help create a heuristic to evaluate and understand social change. It created a revolutionary change in social understanding by appying scientific principles to history and society. It is still a fundamental part of entire academic fields such as sociology, although it has been sanitized by a large extent and his class analysis has been removed wherever possible from “serious” academia.

The development of socialism didn’t end with Marx, but this philosophical underpinning is essential when it comes to understanding the historical development of socialism in China, the USSR, Vietnam, Cuba, or anywhere. The key is that Marxism strives for a scientific understanding of social change and Marxists believe in working with the world as it exists and transforming it into a better world in the context of that reality

China is a large country with over a billion people, and it has contradictions, like any place. Despite the victory of the Chinese people over colonialism, Japanese imperialism, and compradore-capitalist reaction, the newly minted Chinese state, the PRC, was undeveloped and impoverished. Despite historic gains made during the Mao period (the quickest rise in life expectancy in human history) the development in the country was still uneven and it became clear during the Sino-Soviet split that survival itself would require a realistic appraisal of geopolitics and concessions that might prioritize the survival of their political system and their economic development over other important principles. This is somewhat comparable to the NEP period in the soviet union that Lenin described as a retreat.

China made a bargain with US imperialism to open itself up to foreign capital and to allow market forces to exist within parts of its economy. This would ease the threat of imperialist military encroachment, allow their economy to develop, and give them access to technological development… for a time. The existence of markets introduced contradictions and social problems they would have otherwise avoided (like exploitation, including instances of child labor in the private sector, and the creation of billionaires), but China did not surrender political control to capital and maintained state control over vast parts of its economy. It also maintains control over its own trade.

You can tell China did not surrender political control, or its state has not become capitalist in character in two major ways: it did not experience the social disintegration, corrupt firesale of public assets, and economic decline that the Soviet Union, and Eastern Europe at large, explicitly ended their socialist systems (undemocratically, I would add). The second way is that as China has made a leftward turn and asserted control over markets to maintain social development for the good of its working-class, US/EU capitalists have been screeching and wringing their hands and the US has begun a feeble attempt at decoupling and military containment. It was somewhat an open question until that point, but mostly to outsiders.

If you read their documents and perspective as they write it, it is clear they were primarily evaluating the world and making decisions as Marxists the whole time … although the CPC is not monolithic and their internal factions certainly has elements of liberalism within them at times. Even the market reforms have always explicitly been done under the notion that they were not completely abandoning socialist principles, but neoliberals and capitalist realists were quick to think that any level of economic liberalism would inevitably lead to political liberalism. Given what occurred in the 90s, it was a bleak but not unrealistic assumption

I think what you and other folks could do with realising more is that China is an absolutely massive country with a population far exceeding that of somewhere like the US. The answer to all of your questions except maybe (1) is “it’s complicated”. There are massive differences not only between rural and urban areas, but also large deltas between policy, compliance, and enforcement, in almost all areas. The life of, say, a young professional in Shanghai is closer to a similar lifestyle in London or Toronto than it is to that of a migrant construction worker in the same city, whose lifestyle is vastly removed again from that of a traditional village dweller in Xinjiang. For each of those there will be different levels of policy, compliance, and enforcement when it comes to something like surveillance, religious practices, or age of entering the workforce. You won’t get any real understanding of China by abstractions or generalisations, or even by reading policies or laws (and that applies to both detractors and supporters).