Did you read the article? ByteDance's headquarters is in Beijing and these leaked audio tapes are talking about engineers in the headquarters logging into U.S. servers.
This isn't some smoking gun about CCP surveillance, but more about how the sausage is made for a global app.
A courtesy also extended to Beijing [1].
[1] https://www.buzzfeednews.com/article/emilybakerwhite/tiktok-...