Let us begin with the fun stuff.

In his wonderfully funny but also pointed and touching bit of memoir, "Since My Last Confession", Scott Pomfret adopts a delightfully camp tone to describe the personnel, priestly vestments and equipment of the Mass. (In an extended metaphor, the Mass becomes a white linen restaurant, the priest is the chef, Eucharistic ministers are waiters, the chalice is the wine glass.)

This camp tone is entirely appropriate: there is much in the liturgy itself, in church architecture and decor, with its blend of high art and low kitsch, which is itself high camp, and appealing to the gay sensibility (if such exists). Elsewhere, Pomfret notes that Sunday evening doughnut supper in a particular Boston parish, is the best place outside a gay bar to pick up a man on Sunday night.

On a similar theme, Mark D Jordan ("The Silence of Sodom")describes a certain type of Catholic gay man who tends to get deeply involved in the minutiae of liturgy planning.  These men he describes as "liturgy" queens, drawing a clear comparison with that other well-known stereotype, the opera queen.  (In this context, the well-known Marian prayer, "Hail Holy Queen" takes on a whole new meaning!)

On the other hand, what is one to make of the display of the near naked Christ on the cross, and the depictions of the passion in the "Stations of the Cross" found in every Catholic church?  Do these have a special frisson for the SM /Leather sub-group of gay men?  It is certainly so that renowned mystics such as St John of the Cross have developed a whole school of spirituality on the idea of contemplation on the body of Christ - and couched it in language that is remarkably sensuous, even erotic.

Priesthood & Training

It's not only the gay men in the congregation that respond to the camp. It's well known that an astonishingly high proportion of Catholic priests are gay.  There are no reliable statistics, but the guesstimates I have seen tend to cluster around the 50% mark, give or take 20% either side. Nor are these all in the lower ranks, nor should we assume that they are all celibate:  rumours and allegations of sexually active gay bishops, cardinals, Vatican officials  and even popes are commonplace. (Some conservative factions in the Church even claim that all three popes immediately after Vatican II were gay, and that Paul VI in particular ushered in a "homosexual mafia" to the Vatican staff - possibly explaining the reactionary lurch under John Paul II and Benedict XVI?)

Why should this be so?  It is probably simplistic just to blame it on the desire to wear the priestly drag (where else can a gay men get to wear skirts public outside the theatre or drag shows?), but the camp style probably does have something to do with it.

More important though, as Mark D Jordan has persuasively shown, is that the entire culture of priestly training in all-male seminaries is deeply supportive, even encouraging, of a gay orientation, just as it discourages

straight men. Jordan also shows, scandalously, that it is not just the students in these institutions who are, or first become, sexually active in the seminaries: many staff members are sexual predators, taking advantage of the students in their care - even as they warn against forming "particular friendships" with each other.

History

In the Church's long past, carefully airbrushed out of official history, are hidden numerous examples of gay, lesbian and even transvestite (FTM) saints, bishops, and popes. Fortunately, modern scholars no longer depend on clerical approval, and this gay past is now being recovered for us(See the work of John Boswell, Alan Bray, and Bernadette Brooten just for starters.)

Far from opposing gay marriage, for many centuries the church recognised and liturgically blessed same sex unions:  at the start of the relationships, by the ceremonies of "adelphopoesis" in the Eastern church, and by the "ordo ad fratres faciendum" in the West.  Both these terms referred to the making of "sworn brothers", and may have been largely about contracts of property arrangements - but that is exactly what opposite-sex unions were about at the time.  The concept of marriage as the consummation of romantic love is a modern invention.  Many same sex unions have also been recognised in death, right up to the 19th century, by being buried in shared graves, often inside church buildings, or with grave monuments, memorials and inscriptions inside the churches comparable to the memorials to married couples buried together.

Does it matter?

That there is at least a strand of homophile or homoerotic culture, sensitivity, and activity in the Catholic Church is clear.  So what?  Should we care?  For those of us in the Church who are gay, I believe it matters immensely.  By recognising the hypocrisy, it becomes easier to stand up to the theological bullying, and to counter the lecturing with rational argument.

Further reading:

Books

Scott Pomfret, "Since My Last Confession" 
Mark D. Jordan, "The Silence of Sodom" 
Alan Bray, "The Friend" 
John Boswell, "Christianity, Social Tolerance and Homosexuality" 
John Boswell, "Same Sex Unions in Pre-Modern Europe" 
Bernadette Brooten, "Love Between Women" 
Engel, Rangy: "The Rite of Sodomy"