That the song is about the Church of Satan is obvious from both the lyrics and the Hotel California album cover. Consider the following:
• The Eagles were well-known Satan worshippers.
• "The Eagles" can be rearranged to spell "gales (of) heet," meaning the winds of hell.
• An old Christian church in California was abandoned in 1969 and taken over by the Church of Satan. It is this church that is referred to by the lyrics, "We haven't had the spirit here since 1969," and "This could be Heaven, this could be Hell."
• It is in this church that Anton LeVey (referred to as "the master" in the song) wrote The Satanic Bible, and because he let his followers stay there while he was writing, it became known as the Hotel California.
• The lyric, "They stab it with their steely knives, but they just can't kill the Beast," refers to the enduring power of Satan.
• Members of the Church of Satan often have to lie about their membership (just as they are encouraged to lie as a matter of course), and this is referred to in the lyric, "What a nice surprise, bring your alibis."
• Church of Satan members take an oath that is binding even after their death, hence the lyrics, "You can check out at any time you like, but you can never leave" and "We are all just prisoners here of our own device."
• On the Hotel California album jacket, High Priest of the Church of Satan Anton LeVey appears in one of the windows.
• On the back of the album cover a dead man -- sacrificed by LeVey himself -- is shown propped up by a mop.
• The Hotel California album was a best seller, which it couldn't have been without help from the forces of darkness.
Truly, any non-Satanic interpretation is disingenuous at best.