I'm with the rest of the commenters here in being puzzled about why TikTok is being singled out here with respect to the other social media apps. It's like comparing whiskey, vodka, and tequila in terms of health risks. You can't single out one as particularly pernicious when they do about the same thing.
2. Some people are worried about the CCP exerting control to learn about sensitive leaders and their families [1] or to persuade populations at scale [2]. The app has been shown to capture all keyboard input [3], clipboard contents [4], and record much more than it needs to function. Furthermore, all US-based social media is blocked in China, and there's an argument for reciprocity. The topic of Facebook being used to gather international intelligence for the US is not typically mentioned in the same conversations.
[1] opinion; https://www.wsj.com/articles/on-tiktok-its-all-fun-and-games...
[2] https://www.economist.com/interactive/briefing/2022/07/09/th...
[3] https://www.notebookcheck.net/TikTok-is-monitoring-all-keybo...
[4] https://threatpost.com/tiktok-to-stop-clipboard-snooping-aft...