To be clear, "having data stored in China" is exactly equivalent to "had given the Chinese government backdoor access to personal data" - and that's not some "conspiracy", that's the stated law of China.
Furthermore, the reason that's so important is because "having some data stored in China", if true, means that this quote from the article, "Konnech said none of the accusations were true. It said that all the data for its American customers were stored on servers in the United States and that it had no ties to the Chinese government." would be a complete lie.