According to this saying, outsiders see things more clearly precisely because they are not within the system they are observing. There is a lot of truth in this. I strongly believe that being half Italian and having spent so many years, including formative years, in Italy has given me invaluable perspective on my own country, the United States. And I can also see Italy from a non-Italian viewpoint. But it is also true that an outsider's view may be distorted by ignorance, resentment, hostility, and all sorts of nastiness. All and all, some well-disposed, well-meaning, perspicacious outsiders may have a very useful contribution to make in understanding a social phenomenon.
(in the photo, a mother sparrowhawk teaching her chicks to scrutinize and criticize other species)