There should be a real ethical dilemma here for zoo people but most do not want to face it.
At our Zoo Aquarium Association conference last August we heard from a bloke from TRAFFIC. He told of literally thousands of animals confiscated from smugglers. Many of these were specimens of CITES 1 species. They can't be returned to the wild because their provenance is not known. Being wild caught, their genes would be immensely valuable to zoo captive breeding programs around the world. Yet the vast majority of these animals are destroyed. Why? Because that way a message is sent to the smugglers and potential smugglers that smuggling doesn't pay.
As the numbers of confiscated animals is not decreasing, it would seem that this "message" is not having any effect. Sadly, not one zoo person at that conference wanted to tackle the subject - except for you know who!