Shein is a Chinese company itself, so they wouldn't really be hypocritical here. Is it better or worse than an American company profiting off of Chinese goods at the expensive of American worker/economy and environment? I guess we could just keep the goods all out, but the distributors aren't going to survive if it is allowed and they don't do it.
I don't see how they do it "the expense of the American worker". It's a Chinese company founded in China by a Chinese man and selling worldwide online, it's perfectly normal for them to make their product in China.
Shein sells worldwide. H&M (mentioned elsewhere in this thread) and other US brands don't ship to most countries in the world, if they ship overseas at all.
They may trade in 75 countries, but I'll say again, the vast majority of people in the world can't go online and buy from H&M. They won't ship internationally.
A guy in Samoa, Pakistan, or most other countries can't go to hm.com and buy anything.
Pretty sure H&M is not a US brand given all the H&M shops I saw in Europe long before I saw any in the USA. According to Wiki, they are Swedish. They also have stores in China.