Would you accuse the Seattle coffee industry that can roast and drop ship a custom bag of coffee in under 3 days of running on slave labor? Would you accuse the California software industry that can produce an MVP web app over the weekend of slave labor? No, of course you wouldn't. But we do that for China because we assume that it's still the world's sweat shop rather than the world's most sophisticated manufacturing hub.
China is the Silicon Valley of textiles (and it's the Silicon Valley of many other manufacturing industries). Chinese factories that generally pay better wages that afford much better conditions than other textile hubs and can pump out high quality products very quickly. Luxury clothing brands depend on China and generally not a lot of other textile-producing countries for their best quality items.
What Shein, Temu, and AliExpress are actually doing in the market is streamlining the overseas shipping process to cut down delivery times that used to be unreliable and take months with poor tracking and changing that to a generally reliable 8-12 business day shipping infrastructure.
Making the assumption that these websites only sell landfill-bound junk is an assumption that a competing business will make at their own peril. The way I see it, canceling my Amazon Prime subscription and moving most of those purchases to AliExpress has resulted in lower costs with equal quality.
I'm not saying that Shein's quality specifically is any good, but if you haven't been paying attention, clothing quality at mainstream Western stores like Walmart, Target, TJ Maxx, Ross, Zara, H&M, etc, isn't really much if any better than the low end no-brand stuff you find from China.