There are plenty of US companies that are authorized to use government-funded patents, that would prevent them from transferring ownership to foreign owners. This isn't a "poison pill" conspiracy, this is standard export control for state-funded technology.

Any non-arms companies in that mix?

Merck (not an arms company) was expropriated from Merck.

From the Germans, during WWI.

Yeah sure. At least WWI Germany wasn't committing two genocides.

Companies that are export controlled have military tech. The idea that a social media app would have a poison pill for export control is ridiculous and shows how owned these supposedly independent companies really are.

ITAR applies to many technologies that are trivial to duplicate or have been redeveloped outside the US to bypass those restrictions. Memory chips hardened for space are subject to ITAR. These memory chips are commercial with lead tape on them.