I've heard the official story is because it is less costly to build, heat, maintain without windows. However, it is very metaphoric, don't you think? Once you go in, you cannot see the outside world, and people cannot truly see what goes on within that "building" without stepping completely inside? Very cloistered. Very wombish (in a hellish sort of way). Very creepy.
Though I went to a hall one time that had a window in Colorado and I could not stop looking out of the window. I was out of the organization in a very short time thereafter.
I think so much about this religion is either designed or just inadvertantly subjugating to the human spirit and soul. Even down to the lack of windows. No doubt, some people still need spiritual wombs but it's not one with any escape; any window; any egress.
Besides, it is a fire hazard not to have windows.
~B.