I thought finetuning data can't contradict foundation models, and anything that are inconsistent with the standard LLM American-Chinese split personality would be rejected?

They could apply the Polder Model of consensus decision making with a mixture of experts.

https://en.wikipedia.org/wiki/Polder_model

This gets better short-term results for a fraction of the cost, for sure, but what do you when China places an export control banning the release of open weight models? If you don't have your own talent, you're then relegated to using a base model from 2026 or whatever the cutoff date is, forever. That defeats the purpose of a 'sovereign' model made for and by your people.