Why did Hershey's chocolate close the factory not too far from where I grew up, and move the manufacturing to Mexico? Well, labor is cheap there because there are no unions, few health and safety regulations, few workers' rights groups. That makes it much cheaper to operate.
Why can China manufacture clothing cheaply? Well, they have hundreds of thousands of Uighur prisoners being 're-educated' via forced labor.
And while I don't disagree that for some countries that are trying to move up in development, so-called 'sweat shops' can represent a stepping stone forward (2 generations ago, South Korea had plenty of them), the question is how long that's an acceptable excuse?
In my opinion, we need trade rules that explicitly tax and tariff those countries who are only finding comparative advantages through exploitation and unethical activity.