Maybe because they're not all empiricists, naturalists, or materialists? There ISN'T an answer! "Athiesm" doesn't say anything about the person besides them not believing in god or gods! It doesn't say anything about their affinity for science, or their insistence on evidence or even rejecting faith, the word only rejects a few specific spiritual concepts!
If you're going to talk about people with the beliefs you are assuming, may I suggest you not attempt to use athiesm as a catch-all? It simply isn't accurate.
Agreed.
Hence my point about MY not talking about ghosts, psychics, et al. when it comes to the supernatural. I will admit that I didn't clarify myself well enough, but when i was talking about the supernatural, it =/= ghosts, spirits, psychics, etc.