Why do they care about global usage though? This seems primarily so that they can control it for their billion plus population, they really don't need global users at all, much to our chagrin.
Soft Power, both in the obvious and the less obvious sense.
A model is never neutral. A model is always also a way of disseminating an ideology, and it doesn't need to be lying for that to work.
Consider the question "what caused the French revolution?"
There's many ways to answer this while being technically correct. What gets prioritized, what gets omitted, that's where the ideology lives.
Probably the same reason that Meta gave: it's less important to control it, and more important to prevent someone else from controlling it entirely.