Why is the term “nation state” used to refer to a government-sponsored effort in infosec, and is it accurate?

I work in infosec and as such, have read many whitepapers and been to many conference talks. I hear all the time, especially in conversation and literature about malware, the term “nation state” used to refer to a government entity or government-sponsored activity. The term “state actor” is also used.

My question is, why? According to Wikipedia:

A nation state is a state in which a great majority shares the same culture and is conscious of it. The nation state is an ideal in which cultural boundaries match up with political boundaries.1 According to one definition, “a nation state is a sovereign state of which most of its subjects are united also by factors which defined a nation such as language or common descent.” It is a more precise concept than “country”, since a country does not need to have a predominant ethnic group.

According to Merriam-Webster, the definition is:

a form of political organization under which a relatively homogeneous people inhabits a sovereign state

Is there some inherent need for the government sponsor to be primarily of one ethnic background in infosec literature? I just don’t understand why this term in particular is so frequently used, when there are many forms of states, such as a federated state, multinational state, or even more general terms such as “government” or “country,” all of whom would likely be capable of and do participate in infosec activities.