Some components made in China may be as good as (or even better than) the same components made elsewhere, whether they are built in a manufacturer's own plant or outsourced to a third party. But that doesn't change the fact that they are Chinese made. All cars contain some components that are made in China.
While some Chinese-made components are great, not all attempts to offshore production to China are successful in terms of quality control, in spite of the best efforts of manufacturers. There are plenty of case studies of failed attempts to maintain quality. In some cases production has been shifted back out of China as a result of quality control problems. The lesson from years of experience is that shifting production to China is always a bit risky. From a quality standpoint it may work out great, but that is not always the case. You can't just assume that because a manufacturer tries to maintain the same standards that they will be successful. And by the way, while Apple has been a success story, their final products certainly are not "perfect".
Finally, it's not just about quality control.
People have a variety of reasons for wanting to reduce their purchases of Chinese-made goods, including political reasons. I won't rehash all of these.
Doug