Nick Fury says in Original Sin that the list of people that know that the Watcher exists is very short. Ignoring the fact that the Watcher has been seen in public multiple times (Galactus 1st apearance, Secret Invasion), in Amazing Spider-Man there was a kid whose name was Uatu, because his parents were Fantastic Four fans, so they clearly knew who the Watcher was. How does that statement make sense? Just saying that very few people could pull it off is all the info we needed.