Gillian doesn't like being in the lifestyle. Having to hide all the time, to lie about your identity; the hedonism; the endless affairs. She wants to live a "normal life," with a husband and kids. She falls in love with publisher Shep Henderson and leaves the lifestyle, in spite of the admonitions of her Aunt Queenie and fey "brother" Nicky.
Nicky invites Sidney out for a drink and comes out to him -- "You're closer to one than you think." Soon the two are inseparable companions, working on a book together, no doubt lovers as well.
Ok, Bell, Book, and Candle (1958) is "really" about witches, one of the witch-as-persecuted-minority vehicles that continued with Bewitched and Sabrina the Teenage Witch. But it couldn't have more gay symbolism if it tried.
Actually, it was trying. The details about "the lifestyle," Gillian's desire to be "normal," Nicky's seduction of Sidney Redlich, and the drag queen aunties all reflected books like The City and the Pillar (Gore Vidal, 1948) and The Homosexual in America (Edward Sangarin, 1952) which were starting to reveal the existence of gay people, "hundreds in Manhattan alone." Playwright Jon Van Druten, who was gay, also wrote I am a Camera (1951), based on Christopher Isherwood's Berlin Stories, about the gay subculture of 1930s Berlin.
Many of the stars had gay connections. Kim Novak (Gillian) attended the parties of 1950s gay Hollywood with Tab Hunter and Rock Hudson. Elsa Lanchester (Queenie) was married to a gay man. Ernie Kovacs (Sidney) portrayed a number of lisping, mincing "pansy" characters on tv. And in 1959 Jack Lemmon (Nicky) would star in the quintessential absurdist gay comedy, Some Like It Hot.