I don't get it. It's US companies standing to loose their stronghold (near monopoly) on social, advertisement, and other forms of monetizing the web if the US creates a precedent for "national security" in this way, as in "we're welcoming social networks and free speech as long as it benefits the US and can be searched without warrant." Quite predictably, governments all over the world will be pressurized to question…
There's already various international issues with CCP-affiliated companies, but there must be some ulterior motive to go after TikTok and WeChat with such urgency right now, as opposed to any other time in the last 4-5 years.
* Personally, I think the result of what happens to TikTok, WeChat, or US app stores over Chinese apps doesn't matter in the end. What matters is that demands on Chinese apps to come to a deal with the US by September gives Trump more firepower to work with - if the deal happens, Trump paints himself as a US savior from Chinese meddling; if the deal doesn't happen, Trump blames China entirely as the bully and pushes America to retaliate.