Grindr got sold off by the same reasoning and no one complained because it’s a legitimate concern.
I will not pretend that we will look back on the TikTok debate and be appalled by it in the same degree but let's not forget that we considered internment camps to be "debatable" and Americans overwhelmingly supported them [0]. What we call "plausible, if debatable" now is not what future-us will necessarily call it. I think the original commenter was simply pointing out the extremes of the "power" behind using "national security" as justification.
[0] https://exhibitions.ushmm.org/americans-and-the-holocaust/ma...
The power was vested first by executive order, then codified by legislation in the 80s, and was updated in 2006 and 2018.
1. Issued by Trump on August 6, which uses the International Emergency Economic Powers Act.
https://www.whitehouse.gov/presidential-actions/executive-or...
This executive order was stopped by a preliminary injunction issued by Judge Nichols, who based his decision on an explicit exception in the International Emergency Economic Powers Act:
"
(b)Exceptions to grant of authority
The authority granted to the President by this section does not include the authority to regulate or prohibit, directly or indirectly—
(1) any postal, telegraphic, telephonic, or other personal communication, which does not involve a transfer of anything of value;
…
(3) the importation from any country, or the exportation to any country, whether commercial or otherwise, regardless of format or medium of transmission, of any information or informational materials, including but not limited to, publications, films, posters, phonograph records, photographs, microfilms, microfiche, tapes, compact disks, CD ROMs, artworks, and news wire feeds. The exports exempted from regulation or prohibition by this paragraph do not include those which are otherwise controlled for export under section 4604 of this title, or under section 4605 of this title to the extent that such controls promote the nonproliferation or antiterrorism policies of the United States, or with respect to which acts are prohibited by chapter 37 of title 18; ...
"2.
An executive order by Trump based on CIFUS, which is forcing a divestment of TikTok's acquisition of Musical.ly (whose founders are Chinese but operated the company in the US). If not, the order would bar TikTok from operating in the US.
https://www.whitehouse.gov/presidential-actions/order-regard...
The part of the order that would bar TikTok from operating in the US was halted by an injuction by Judge Wendy Beetlestone. Although she did not opine on the divestiture.