In the "realpolitik" environment you mentioned, when you lose control of your private information, you lose control of what's done with that information. That's is a good reason to care about protecting information and not regard this as "completely separate".
An example that people mention a lot in the domestic context is that laws and governments can change, so that information that was innocuous before could be sensitive in the future.
Someone doesn't need to have jurisdiction over you in order to harm you with your secrets. They could taunt you about them, they could blackmail you with them, they could use them to compete with or undermine your business, they could pass them to your government as a tip, they could reveal them to your political opponents...
You might say that this is all Reason 2 and not Reason 1 material, but if a government has unauthorized access to secret information of its choice, it's going to be hard to control or predict how it may use that information against your interests later. But, you might say, I also can't actually control whether they get unauthorized access to my secrets, so I just have no power over them at all, so why even talk about it?
Well, I'd say that lots of people who read HN have practical opportunities in their careers to engage in espionage or not, to make it harder or easier, to expose it or not, and so on. Governments are going to ask some people reading this thread to do them favors. They can't necessarily guarantee the safety of their own information, but they can significantly affect the safety of other people's information. It matters whether they think that's desirable or not!
