The concern isn’t the input, it’s the potential output. Temu doesn’t have the potential to be used for a large micro-targeted political messaging campaign.
This is arguably more akin to how the US handles TV and radio. There are national security restrictions on foreign ownership.
The concern isn’t that these companies have microtargeting data. The concern is about what these companies could use that data for.
An off-brand t-shirt site would be a fairly ineffective vehicle for political propaganda. Tik Tok would be great at that.