Because it's just not clear. It depends on if you trust the veterinarians in the lab to provide an objective assessment, and also just believe that they are correct. And I do wonder if they might be correct for some of the animals, but not all, so maybe some should be kept to retire in place, and some should be sent to the shelter.

Regardless, on a more personal note, I wouldn't want to subject my cat to the kind of transportation and relocation they're talking about, regardless of health or age. And I believe chimps are much more self-aware and intelligent than cats; I expect they'd find it much more stressful.

I think this is a case where the law was well-intentioned, but didn't provide any escape hatches for situations not considered by the law.