This picture shows a girl who is obviously a sports fan. Does she know the players personally? She probably does not.
These people are fans at a concert. Do they know the singer or band personally? They probably do not.
Lastly, this picture shows fans of celebrities trying to capture images of them; but do they actually know them? The point is that these are simply fans who do not have a personal relationship with their obsessions. Similarly, if the gospel is not presented in it's fullness to people, then it is possible that fans of Jesus are created but not true followers. A follower of Jesus is taught that they can know Jesus personally.