China is large and diverse country, so I don't think its fair to pigeonhole them with blanket statements. It's like saying all American made goods are high quality or all American made goods and trash quality. High quality and trash can both be had from American manufacturers, and likewise from Chinese manufacturers.
The problem is when you are looking to have something made at the cheapest possible price, China is very often the least expensive source for manufactured goods, and you tend to get what you pay for. If you are a manufacturer willing to cut corners for higher margins, than yes, there are plenty of Chinese factories that will take shortcuts on quality control to hit your price point. However, if you are willing to pay for very high levels of quality control, there are Chinese manufacturers who are as good as anyone else in the world. However, the problem with high QC Chinese goods is that you don't actually save a lot of money versus manufacturing in other countries. I have talked about this issue with multiple audio manufacturers. In my opinion, it's not China in particular that is the problem with low quality goods- its greedy shareholders and cheapskate consumers who don't want to pay a fair price for high quality.