Answer:
Perhaps because they are the national symbol which means more people will likely recognize them than a smaller organization or institution. They also represent the nation which means other countries will see them more often than smaller human institutions and like on national TV or a UN meeting more people will likely watch that than any other politics channel. It's like a huge national restaurant change compared to a smaller local business. If you are in a city other than your hometown or a more familiar place and you see a McDonald's and a restaurant locally owned that you'e never seen before, you'll probably head to the McDonald's. It's also about who the majority will trust, watch, support, or talk about.
Explanation: