The Chinese have a reputation for bad Q&A
This is probably off topic but this kind of smearing has to be refuted.
Chinese have been making products for some of the high end premier brands for years. We haven't heard many complaints on QA for those products. China wouldn't have become the No. 1 manufacturer in the world simply by being cheap. Many of the top 500 companies wouldn't have had their products made in China either.
The low quality Chinese products that many are making fuss about are, in fact, "by design". These products are meant for the lower end market. No denying that some of them are too cheap to be usable. But one gets what he pays for. Expecting high quality from such products is just absurd.
How much an end user gets from QA is proportional to how much he pays for the final product. That's the same in any step of making a product, be it a phone, a car or a kettle.
Now back to airplanes. The Chinese aviation industry was so out-of-date until only two decades or so ago. The crude finishes we saw in J-7, J-8 and even in J-10A were just showing the industry's technological capability of the time being. As the industry is catching up, we now see dramatically better finishes in J-10B, J-20, etc.
Last but not the least, such crude finishes in miltary airplanes might have been partly due to design specs. When radar stealthness wasn't a hard requirement, having pretty skins were probably not a priority to the designers and workers.