It is perspective. From the Iranian stance, NSA is an APT and theirs is not. Likewise the UK version, Russian versions etc.

Them / Us.

Sure they are. https://en.wikipedia.org/wiki/Equation_Group

It's probably more about convention and terminology. Security researchers tend to label foreign actors as APTs partly for tracking and reporting purposes. With domestic agencies, especially US ones, there's either reluctance or it's treated as a given.

Because it's not wrong when "we" (i.e. those naming who counts as APT) are doing it.

Remember the Snowden leaks? They are.

WTF is an APT?