I don't really see your point. Tiktok is a video library. With the exception of private videos, anything hosted on the app can be viewed by anyone. Whether or not the app provides a personalized algorithmic selection of videos does not have any bearing on the more fundamental question of whether American's have the right to access foreign media.
Since when are social media apps considered broadcasters? In fact, section 230 legally protects social media apps from the civil liabilities of broadcasting. You're also just distracting from the actual issue. Being that, as citizens of a democratic republic promoting free speech, press, association, etc., do you think we have a right to view foreign media (including broadcasts for that matter)?
Of course it's relevant. TikTok should be considered a broadcaster. We have not allowed foreign ownership of a broadcaster since 1934.
A book does not broadcast in the same way.