I doubt Zuck is underestimating TikTok. He has spent a 13 years living and breathing social media, has surrounded himself by smart people, has access to masses of data others don't, and has shown a willingness to admit making mistakes.
Taking his Q&A responses at face value is a mistake. There is a huge element of PR in his response. He is undoubtedly very aware that anything he says has a decent chance of being leaked to the press.
Taking his Q&A responses at face value is a mistake. There is a huge element of PR in his response. He is undoubtedly very aware that anything he says has a decent chance of being leaked to the press.