it's a practice reaching as far back as cartography itself
The old projections systems were even made to blow up what you cared about (your country) and be very scale-imprecised on the outskirt.
That might be less propaganda, and more about wanting a large, precise map of the area that interests you.
Projections were chosen for a variety of reasons. For example the Mercator projection distorts the size of things far from the equator, but it does preserve local bearing and shape.