This linked conversation from Slate in 1999 allowed me to find, finally, critic A.O. Scott's explanation of how much the Harry Potter series speaks to gay readers:
What I mean is that being a wizard is very much like being gay: You grow up in a hostile world governed by codes and norms that seem nonsensical to you, and you discover at a certain age that there are people like you--what's more, there's a whole subculture with its own codes and norms right alongside the straight (muggle) one, yet strangely invisible to it. In out-of-the-way spots in the middle of large cities are secret places--bars, bookshops--that cater to this special clientele, and suddenly, one day, you find your way to them. The reaction of many straights (muggles) is hostility and denial, on the order of the Dursleys. But some muggle parents, like Hermione's, love their wizard children and support them. (Hermione reciprocates by taking a course at Hogwarts in muggle studies, the one moment in the series that made me laugh out loud.) Consider too that there are wizards born of muggles and muggles born of wizards, so that having magical power (like being gay, at least according to some schools of thought) is, while not hereditary, clearly innate. Your use of the phrase "a place for us" was especially suggestive (though by "us" you meant the muggles), since that's the title of a fascinating book by D.A. Miller (published last year by Harvard) about the role of the Broadway musical in forming, at once in secret and out in plain view, modern gay male cultural identity. The process of acculturation he describes (which involves playing the cast album from Gypsy in your parents' suburban basement), is not unlike what Harry undergoes in the early chapters of Sorcerer's Stone.Scott makes an interesting case; while this surely was not J.K. Rowling's intent, it does help explain why I'll be reading as fast as I can all weekend. To those of you who will be doing the same: I wish you a gay old time!