It's not even about them:

> If, for example, a user allows TikTok access to the user’s phone contact list to connect with others on the platform, TikTok can access “any data stored in the user’s contact list,” including names, contact information, contact photos, job titles, and notes. 2 id., at 659. Access to such detailed information about U. S. users, the Government worries, may enable “China to track the locations of Federal employees and contractors, build dossiers of personal information for blackmail, and conduct corporate espionage.”

https://www.supremecourt.gov/opinions/24pdf/24-656_ca7d.pdf

It seems farcically ridiculous to me to ban the app because it somehow could let china blackmail CEOs.