Im not discounting the comment OP’s observation, but I think it’s also important to consider the inevitability of an outbreak like this in light of invasive species, non-species, and not-so-genetically diverse farm animals.
What’s often missed by the lay-folks is that there’s plenty of wildlife that is capable of contracting and transmitting these diseases. Sure, many zoos have intense quarantine protocols, but if zoo animals have any overlap with local wildlife, they are potentially exposed to disease. Many zoos (at least that I can think of) do not keep out local wildlife—be it pigeons, house sparrows, or squirrels.
Bags of chickens from a local, shitty farmer trying to get rid of sick birds? Possible, if a little conspiratorial. Ubiquitous wild animals interacting with zoo animals and livestock? Probably a little more likely (at least to me).
Source: me, I’m a biologist, albeit not a disease ecologist.
I think I agree with you in general. My point is more that we tend to forget that wild animals are among us everywhere and we really do need to take care to be aware of that, but maybe I didn’t communicate that well.