The law underlying this deal isn't a privacy law but a national security law that allows the President to force the sale of foreign-owned assets that pose a security risk. It's mainly intended to deal with war, near/imminent war, and quasiwar situations where the assets are active tools of opposing belligerent, and, even if this is technically within the letter of the law (about which there has been serious questions raised), it's seems clearly outside of the intended application and to be very likely premised on a bad-faith determination that is an abuse of power. But the Republicans in the Senate have already signalled a lack of willingness to hold the President to account for any abuse of power no matter how flagrant, so everything that isn't forcibly constrained by something other than the risk of impeachment is, de facto, licensed until the Senate and/or President are changed.

Nah there definitely is. There is no rule of law regarding international deals besides what can be enforced with violence or the threat of violence. That’s why, for example, the EU has different trade rules for different countries, protection mechanisms for domestic products and industries, etc.

Why is the UK working on a deal? Shouldn’t the EU provide the same deal to all countries? Nah. It’s “tit-for-tat”.

Strong economic, biologic, and anthropologic research shows that tit for tat is the very foundation of civilization.

https://ncase.me/trust/

"Rule of law"? This is international relations. What "laws" do you speak of?

So what should the US do when China does not allow some US companies to operate in China?

“There is no such thing as tit for a tat in a civilisation with rule of law.”

That’s not a general principle of which I’m aware. Plenty of countries have rules like “we treat you how you treat us”. Nothing about that is inherently incompatible with the rule of law.

The world is not black and white.