Asklemmy

It wasn't slave labor, exactly, but it was massively exploited labor. 75 years ago China was easily the poorest country in the world and it's people were living in the equivalent of $1/day, possibly less.

However, the entire goal of the socialist program was to alleviate that poverty and exploitation, not by enslaving people but by developing the country's economic and industrial base.

Today, Chinese people have a higher average purchasing power than US citizens do. That means the average Chinese family can afford to buy more goods and services than the average American family. Wealth inequality is also way lower in China than in the US which means that way more of Chinese people have better purchasing power than USians do, simply because that's how averages work. The US raises the average by making very few people very wealthy and China raises the average by making their billion residents sustainably and incrementally more wealthy.

As for slave labor, the US imprisons more of its people than any other nation on the planet and all of those prisoners are subject to slave labor and massive debt burdens. Official US slave labor from prisons produces over $11Bn in goods and services, much of which goes to the profits of for-profit prison management companies.

China has no such system.