You are incorrect about sitting in one place and doing the same action over and over. I have done consulting work at multiple vehicle MFG plants in multiple states and have seen it first hand. I have seen it in passenger vehicles, semi MFG, bus MFG, etc... A prime example is wiring harnesses, but there are many others if you move around the facilities.
Oh and while you make it sound horrendous, and I personally would never want to do it, a lot of workers have worked there for decades, some 30+ years. They could have easily transferred to a different department. Some do, some move around, some stay put. They also could have got different jobs in the 30 years they have been doing it. But unlike maybe you and me, some people just like that type of work. They like the structure and consistency.
I don't condone forced/slave labor and I am not going to get into the woes and politics of global manufacturing, I will just say your comments on sitting in one place and doing repetitive work is utterly incorrect and not just in vehicle manufacturing. I have seen it in medical equipment, binocular, knife, and tech component manufacturing. All US based and all essentially the same MFG line process as used to produce things overseas. Doesn't mean the pay or conditions are the same, but again avoiding that topic since it wasn't what I felt you needed correction/more information on.