It is irritating that most zoochatters hide behind pseudonyms. And their profiles are of no help and often misleading. I have no idea who they are, often no idea of sex or age, so little hope of knowing what they look like. Although there seems to be a sub-culture where zoochatters interact outside of this forum and many know each other.
I am asking that too, why they are hidding behind imagined names. Maybe to protect from a shame from eventual lapsuses on Zoochat

or are keeping their privacy, and espacially in respect to future emplyoment.
there are any number of reasons why people don't want to use their real names.
First and foremost, Zoochat is a forum for zoo enthusiasts. There are current and former zookeepers, and also
bona fide zoologists, on here - but the majority of members are simply people who like zoos. It is not a professional platform, so there is literally no need for anyone to give their real names.
In some cases there can be an issue of safety, especially for the younger members. And, as TLD alluded to earlier, the internet is full of whack-jobs who you really don't want knowing who you are if they establish a vendetta with your name on it. Especially if you have a distinctive name. You may be unconcerned with letting specific people know who you are, but equally you may not want to broadcast it to the world.
Then there's the issue of professions. Zoos are secretive organisations - they want publicity but only on their own terms. They want people to talk about them in social media, but only when it is along the lines of "ZOMG Baby meekats!!". They don't want people discussing details of their latest conservation success story in breeding hybrid giraffes or white tigers. So there may be members who work in zoos but, even if not speaking ill of any organisation, still need to maintain anonymity. Some members may desire to work in zoos in future. It is routine for employers to Google job applicants - a job at a zoo may not go your way if you have been discussing the irrationality of phasing out species X at zoo Y. Even if you are applying or work at a non-zoo job, you may not want co-workers or management reading what you post on a forum.
There's also the question of whether a "real name" is even real. Anyone can register as Carl Jones or Jack Sparrow. It doesn't mean they are "that" Carl Jones or Jack Sparrow.
I doubt most members on the forum (or even on most forums) actually have anything to hide when they are using a pseudonym - but they still like their own privacy.