If you have the former position, which seems to be embraced by the majority of HN users, you can't accept to have Tik Tok, a chinese controlled social network, taking over everyone under 30 in the US.
How would this not be a major threat? As opposed to bot farms on FB/Twitter controlled by foreign actors?
Bot farms are symmetrical - you can use them to support Democrats or Republicans.
TikTok is asymmetrical - it can be used by the owner to support one side or the other, but users of the platform have no influence on this.
Also, if bot farms can sway elections I would either want them to be pliable to more than just Democrats and Republicans.
With TikTok, the primary determinant of what you see in your feed is what they choose to show you - and it could be from anyone in the world, with any degree of separation from you.