Sounds like either baboons should not be subject of captive display or kids should not be allowed to zoos.

Given how freaked out a lot of people are by the baboons at the Singapore Zoo that are apparently completely healthy (according to all the signs that attempt to reassure visitors, but I remain dubious), but have what look like pretty scary tumors on their buttocks, I can imagine how poorly they would react to actual injuries.

At something like 4 or 5 years old I lived in Pittsburgh. The zoo had an elephant with a red eye that terrified me. These were the days of bars and chains and up close displays so you could see right into its horrible red eye and after it tore aside the bars and snapped its chains it could easily destroy you. (Note: 4 or 5 years old). The elephants were one of my brothers favorites so we spent a lot of time there. I can still see that eye after more than half a lifetime, I expect I'll still see it at the end. (LOTR could have had a much more ominous eye.) I spent a lot of time looking at the animal opposite the aisle pretending there was no elephant, it was in a low cage, I have no recollection of what it was, maybe a marsupial? Now I can hear the elephant shifting its weight back and forth behind me.

Point being, eventually… A zoo probably does not want 4 year old children looking at a baboon with the side of its face torn away to expose the bone. In this case, "think of the children".

Then issue a warning. I actually think it's unethical to hide the animals. The public can't make informed decisions about visiting the zoo if the zoo is hiding the reality the animals live in.

"they closed the exhibit because they didn't want the visitors to see the (potentially unsettling/traumatizing) injuries on the baboons"

Have they tried closing the Zoo and releasing the animals back into the wild. Zoos are a nineteenth century anachronism, designed for when that was the only way people could get a look at such exotic animals. Last time I was in one, the animals looked tired, stressed and listless.

This is a silly argument. Good schools have fun, zoos are informative, and schools don't have surprise baboon battles.

The purpose of school is to lock up kids and adolescents in order to free up the adult population. Any education happening is incidental.

Exactly. And I also wonder how "safe and fed" zoo animals feel, as opposed to feeling endangered by being trapped and/or at the mercy of a different animal (humans).