Microsoft operated its own popular social network in China, called MSN Messenger. Tens of millions Chinese users were on that platform for like a decade until the release of mobile based WeChat.

> which the communist party in China has treated for years as a matter of national security

It is a matter of national security, we all saw what happened on twitter shortly before the 6th Jan 2021 attack.

https://www.presidency.ucsb.edu/documents/tweets-january-5-2...

https://www.presidency.ucsb.edu/documents/tweets-january-6-2...

That is the exact reason why everyone agreed that TikTok must host all US data and its deployed recommendation algorithm code in the US with 3rd party audit access by an appointed US entity.

The only question here is why should Meta and Google be exempted from the exact same rules if they want to operate their services in China.