If it may be permitted to mention something "indelicate"(and having read "Hobbit Sex ed" I hope this will be OK
), there is another category of women who are notably missing, especially in stories involving armies to such an extent and that is those of "the oldest profession". I know that LOTR was written in an earlier age and with the original intention of being a children's book but if we look at categories such as "maid, mother, hag" then "angel / whore" may be opened up as well. Tolkien was far from prudish as stories in the Silmarillion (especially early drafts) and Unfinished tales show.
I find it hard to do more than speculate on this since on the surface the Middle Earth of LOTR (save perhaps the Shire) seems a completely unbalanced society. It almost seems as if it was not only dwarves who had an unequal ratio of males to females. If women are not referred to do we assume that they existed or not?
Unless they have a specific role women are not mentioned and very few women have a specific role. Apart from no Entwives, female orcs, female trolls, female dwarves, there are no serving wenches at the Pony, and from the description of the Feast, Arwen seems to be the only elf-woman in RIvendell. When Frodo says "there was one lady" - he may mean one marked out of particular status but it is weird that no woman is described (that I recall who doesn't have a role in the plot). Even in Lorien, the only reference to elf women other than Galadriel is the mention of the cloth having been woven by Galadriel and her maidens. Again we don't "see" them, are they as sequestred as the dwarf women? In a way the fact that the women of Gondor and Rohan are said to have been evacuated makes the absence of reference to "background" elf women more conspicuous?
Hemingway's "Men without women" has nothing on this. Perhaps "Men without lust" is closer. It is as if sexual feelings are awoken in them only by the sight of the women they are to marry and are confined only to them. Until this happens they seem to lead ascetic (I can't think of a better word though I can't at the moment better it) lives untroubled by "baser" feelings. Male lust seems to be confined to desire for the ring or power and female lust by the insatiable hunger of Shelob. It really does seem slightly unhealthy. And in this light it makes sense that the two characters who are actively interested in girls (Faramir and Sam) are more resistant to the lure of the ring. . Thinking about it the war of the Ring seems just a culmination of an awful lot of unresolved sexual frustration. And without wanting to get very Freudian about warfare, especially warfare largely involving swords and spears - that hippy motto about making love not war starts to make an awful lot of sense !
