For a DJ, the creative part is putting on the show and how they use the music created by someone else to help the audience have a good time. It's the same thing as movies using pop songs in the sound track to set the mood in the movie. It is creative for a good interior decorator to use furniture and rugs designed by someone else to make an interior space be amazing.
That's all recorded music is to a DJ. It's the raw material from which they fashion a show. A good DJ uses this raw material well, and a guy that "plays music" just plays music.