For example, “Washington” (US), “Brussels” (EU), “Moscow” (Russia).
I guess it’s a short hand for writing “US government”, “Russian government”, etc. but why? And what happens when you’re referring to a country with multiple capitals like South Africa?
I think it just makes the article more engaging, less mechanical, more human. It places the article geographically rather than these things happening in an aloof intangible other place. Remember that the article has an audience both within, and outside, the borders of the country it’s describing.
For example, I live in the south west corner of Western Australia. Our political capital is Canberra, not far from Sydney, which must be at least 3,500 km from here. It may as well be several countries away. The landscape is different, the flora and fauna are different, the people are concerned with different things.
It’s quite common for people to refer to “Canberra” in lieu of “the government” to emphasize that geographic and cultural separation.
For example, like most countries I guess we have an app that you need to use to identify yourself to government websites. In the course of my work I often find myself helping people through the process of installing it and setting it up. It’s common enough for someone to complain “I guess this seemed like a good idea to someone in Canberra”, instead of saying “the government is out of touch if they thought everyone could do this”.
As regards South Africa, I didn’t know the branches of government had different capitals there. I guess you’d just refer to whichever one was responsible for the particular action you’re discussing? Or maybe you just wouldn’t use this phrase.