My interpretation of the night elf society and culture
Those are all the things they are not. Of the things they are, they are first and foremost a matriarchal warrior society, but they are not amazons. In their culture males are revered. This is due to a number of reasons. First, females are more likely to be born than males. Second, every male, regardless of disposition, attitude, etc., undergoes the Emerald Dream. In the Dream, their mind and consciousness leaves their current plane of existence and transcends to an alternate one. They do not always wake up or return altogether sane. Most of the ones that return more or less insane are the "YAY! NATURE! Roll around in the grass, hug every tree, kiss every flower" kind of crazy. A vast minority return as the psychopathic, kill everyone, and exterminate all life from the world nutjob. But, most of those who enter the Dream do not wake up, and their bodies waste away into nothing shortly thereafter. Very few actually make it out of the Dream roughly the same as when they entered. These few are kept within the major cities and towns of the Night Elves, allowed to do whatever job they choose as long as they do not leave, and are subsequently used as breeding stock in order to propagate their race.
The not so sane ones are kept within the social centers as well, if they are benign that is. The more violently insane are either locked away in prisons/dungeons, exiled to another dimension, or in a few extreme cases, executed. Execution is a last resort becuase even though they may be a few acorns short of a bushel, they can still be used for breeding.
Since males are treated in this way, there are no male guards. No male commanders in their militaries. The ambassadors to the other races are all female, save a very select few males, and those male ones have an absurdly large security contingent comprised on only females. The ruling caste of their society are the Priestesses, with the High Priestess being the final authority.
Many men out there are probably thinking that all this is not a bad set-up. You get to basically have sex with however many women you want for the remainder of your days; overlooking all the negatives. That is an oversimplification, males are revered, yes, but in that "irreplaceable treasure to be kept behind the glass in a museuma and protected and observed at all times, no matter what" kind of way. Males are revered, but not free.
Now away fromt the whole physical procreation bit, and onto other matters. Night Elves are warriors. They are ruled by their emotions, violent, mean, and altogether not nice to be around. They fight viciously and they fight dirty. They hate losing and believe in getting mad first, then getting even. In most regards they make Orcs and Trolls look positively peaceful by comparison.
They are a sensual people who prefer emotional and physical gratification over the pursuit of knowledge. They naturally live for thousands of years, they can accumulate knowledge and intellect later. On that note they are selfish and unsympathetic to the plights of others. In the various wars they did not step in until their interests were directly affected. If the World Tree had not been threatened, they were perfectly content to watch every other race burn. Probably would have brought refreshments and lawn chairs to watch the show as well. The only race they would possibly intervene for is the Taurens, due to a shared love of nature.
The Taurens, despite popular belief, are a primarily carniverous race, as such they waste nothing of the kodo they follow and hunt on the great plains of Kalimdor. The Night Elves are much the same way, except with trees. They live in, on top of, around, and under trees. They carve their buildings into trees, but without killing said tree. The pieces of wood they removed in order to make the building, are then used to produce furniture and other wood-based products. Their love of trees, and nature due to association with trees, is so great that they are immensely irritated by the Draenai. The same Draenai who had the gall to crash land their ship, due to some stupid emergency, into some of the roots of the great tree that houses Darnassus. The Draenai who dared to looke like the demon, Archimonde, who destroyed their beloved World Tree. So of course the Night Elves ignored all pleas for aid and refused to facilitate transport from Kalmidor to the crashed ship, despite being the physically closest to it and the Draenai. As I stated earlier, Night Elves are mean and spiteful.
The Night Elves are, for the most part, profoundly religious, they are ruled by priestesses. They have one deity, the Goddess of the Moon, Nature, and Everything, Elune. The priestesses and druids of the Night Elves are fanatically devoted to serving Elune and her interests at the expense of everyone else. The warriors fight to protect the priestesses and druids, while rogues do whatever they want, primarily torturing and killing members of other races, mainly because they can and no one can stop them. Their influence is all over Kalimdor because of their once sprawling militarly controlled religious empire that fell with the World Tree. They are working on repairing and regaining what they lost, and are doing a bang-up job of it too.
In regards to military action, with the latest outbreak of warfare across the world, between the Alliance and Horde, Night Elves have grudgingly agreed to work with the lesser, annoying races, to protect trees, nature, and their growing empire. They consider the other races as lesser because of the following: Draenai look like the demon that destroyed the World Tree and killed trees, Humans are short, Dwarves are shorter AND stupid, and Gnomes are even shorter AND stupid AND they whine incessantly. The Night Elves are stuck wondering why the Gnomes complain about the loss of Gnomeragen instead of amassing an army to invade their old home whiping out everything that breathes that is not a Gnome. When they questioned the Gnomes on this, the Gnomes responded that they will not do it because of conflict and because there would be moderate to high casualties. The Night Elves were in disbelief that something as trival as casualties would keep the Gnomes from reclaiming their homeland from vermin. Night Elves no longer talk with Gnomes, appalled by their dislike of conflict and fear of loss of life.
There are virtually no Night Elves in the Exodar with the Draenai or Ironforge with the Dwarves. The Exodar because of their dislike and irritation with the entire Draenai population and Ironforge because the Dwarves associate with the pathetic little pansies that are the Gnomes. Instead the Night Elves have a surprisingly large presence within Stormwind and are on more or less good terms with the Humans. This is due to the Humans love of wanton destruction, indescriminate violence, and unmitigated, general, world-wide warfare.
From this piece you should be able to draw a fairly accurate picture of what Night Elves are and why they act the way they do. Tune in another time for more dissertations on the other various races of the World of Warcraft.