Are you sure about that? Unless you are physically disabled, I wouldn't recommend making sweeping statements about accessibility. As an able-bodied person, I've often been surprised at some of the things that can be inaccessible are, and it's important for zoos to cater to everyone, no matter their abilities, age, height, etc. One place I've noticed this at a number of facilities is with the height of barriers, as oftentimes viewing barriers were placed at a height too high for shorter individuals (including children) to see properly. And zoos wonder why they have to keep reminding people to stay off the fence...
My first thought when reading the comment you quoted was exactly this, that it doesn't sound like a very accessible and inclusive exhibit for people of all ability levels. For what it's worth, I checked ASDM's website, and found this regarding accessibility:
Accessibility - Arizona-Sonora Desert Museum
It mentions 96% of exhibits as being viewable from a wheelchair, and while ideally that would be 100%, 96% is pretty close, and I'd be curious to hear what the other 4% are. If they are newer exhibits, that's inexcusable, but I could understand some older, less accessible exhibits kicking around.