1) Is there a shortage of labour in China? 2) Why do you setup a factory in areas far away from other factory and transport the components far away to Shenzhen assemble and export? 3) Were these workers paid? And were they paid fairly?

I can understand the situation. The Chinese government is trying to improve the economy in Xinjiang and encouraged companies to setup factories there. Ruled by a communist government, these companies had to comply and provide jobs to those areas, which is far from port and industry, whose workers are less trained and educated. China is hoping that by improving the economy, people can forget about independence maybe?

Evil? Kind of. Very practical plan though.

Edit: Distance from Xinjiang to Shenzhen: https://www.google.com/maps/dir/%C3%9Cr%C3%BCmqi,+Xinjiang,+...

4k+ kms, 6+hr flight

One of the reason south China is more developed to northern China is that the south has most factories, it is close to port.