I find it rather odd that a scifi show is viewed negatively for describing an alien way of life...
As for the "Eloqium" thing, it doesn't really sound half as bad as that. Sure, the writers let their minds wander during the creative process and only got them back afterwards, but the end result isn't difficult to rationalize back into the realm of the possible.
What Kes really says is just this:
-eloqium comes only once, usually at age 4-5
-Ocampa females can have kids only when eloqium comes
-a sticky goo and 50 hours of mating are involved in conceiving a kid, which is then carried on the back of the mother
Apart from that, there's lots of abstract discussion where Kes or Neelix wonders if having "a child" is a good idea. However, at no time is there an explicit claim that only one child could be conceived.
It would be rather natural to assume that when eloqium comes, an Ocampa female will simply strive to mate lots and lots of times and get lots and lots of kids. Each will gestate quickly, just like the Ocampa mature quickly after birth, and Kes could thus plausibly give birth to a dozen (singly, or as twins or triplets) before her eloqium runs out. It's not a one-off affair at all, but simply a fancy name for the period of fertility on the species. Human females typically have an eloqium of about 25 years, or a third or a quarter of their lifespan; Ocampa females just happen to have one that lasts a bit less...
(...Or then not. No duration is ever given for the Ocampa eloqium. Kes might have remained in the receptive state for a couple of years for all we know, matching the human standard. Her reasons for hurrying with the first mating might have been complex and not completely rational.)
Kes, of course, would have little or no interest in using up her full child-producing potential. One kid would be plenty for her, as the survival of her species would be completely off her back (rather literally!).
Timo Saloniemi
Actually some plausible explanations here, especially the theory that the Ocampa can have more than one child, probably twins, triplets or more. There are some hints for that in certain episodes.
In "Dreadnought", Kes tells The Doctor that she had an uncle named Elrem. So one of her parents must have had a brother!
In "Before And After, Kes's father Benaren says something about Kes being her "favorite daughter". So they had more daughters than Kes!
Otherwise I din't find it negative to describe alien ways of life. It's just some silly things with the Ocampa mentioned here which in my opinion screws up the species.