What you don't understand could fill the pacific ocean.

When a sweatshop in china offers 2 dollars a day, the person could take that job and improve their economy, or not take the job and try not to starve to death on 1 dollar a day back on the farm. All the jobs you call horrible are actually a boon for those who can land them.

This is exactly where the US was in 1800's. People earned a dollar a day for a full day of labor. That was sunup to sundown, not the 8 hour days that capitalism allows us now. 200 years of progress has made us much better off. It did not happen over night, and it will not happen over night in poor countries today. But we can see the progress.