Considering Roddenberry's secularistic impulses, however, it's not surprising.
"Classic" Trek did indeed have references to Christianity - perhaps it was necessary to be successful in the still-conservative network TV of the 1960's. By the time of Next Generation (which I actually regard as probably the best overall of all the series), however, it's as if Christianity - and virtually every other major human religion - is vacuumed out of human society. There's plenty of Bajoran religion, Betazed religion, Klingon religion, Vulcan religion, little green fuzzy religion - you name it. But by the 80's, Roddenberry and Berman had made a conscious decision not to allow any real world religion to penetrate the Trek universe. Instead, religious issues with dealt with through the prism of fictional alien faiths.
One episode that sticks in my head - and sticks in my craw - was the DS9 episode were Kaiko faced a Bajoran boycott of her class over her insistence on teaching about the scientific aspects of the wormhole, which ran contrary to the tenets of the Bajoran traditional belief of its origin as the home of the Founders (especially remarkable considering that the show actually concedes they exist). The show was clearly a thinly-veiled commentary on the teaching of evolution in public schools - and with a predictable angle.
The remark by Archer noted above thus caught me by surprise. I guess I was so pleased to see at least ANY reference to a human faith that I muted my usual disgust for this perennial annoyance of the Trek universe.
I don't see why Berman & Co. seem to be so afraid to allow human faiths to have some kind of presence in their universe. While Roddenberry may have had some firm belief that humans of the 22-24th centuries would "outgrow" religion, it's fairly obvious that it's unbelievable that many humans wouldn't take faith with them to the stars - any more than they do so today when they go to work or pilot planes or man ships or go to war in Afghanistan.
In other words, it's one respect in which Trek has remained consistently unbelievable.
So far I've surprisingly pleased with "Enterprise" as well - it is leaps and bounds better than the moribund "Voyager" and generally more interesting than the premise-limiting DS9. Hopefully we'll see more of this issue addressed as the series unfolds.
Secondly, it's interesting to remember the world that Rodenberry came out of. I guess he started writing in the 40s and 50s, and I'm sure that the idea of religion slowly dying out over time was widespread at that time. If anything, it's the resurgence of faith (and the conservative movement a la Reagan) at least among some quarters in recent decades which is something which polite, mainstream liberals would not have predicted. I have recently heard some people compare Bush to Harry Truman. What normal, mainstream liberal American would have predicted that we would have a plain-speaking Texan as president in 2002?
Another thing which was big to predict in those days was "one world government", like a super United Nations, which has also obviously not happened.
And hence, this, along with the lack of capitalism, is why I say that Star Trek society is highly illogical.