Whereas this policy may work short term, long term and if adopted across scale by all AZA institutions it will have a disastrous effect on the viability and sustainability of many non focal breeding programs. I am all for focal breeding programs for all species and not just for the conservation dependent ones
The above later after all in a few years time it may well backfire and that what was thought safe is down the timeline become critically endangered. We have seen these mistakes and mishaps happen over time already in not just AZA/North American collections when species are on phase out or with a breeding freeze and suddenly the species is almost lost from collections without a trace. Examples: lion-tailed macaque, silvered leaf monkey, Carnivora? (I cannot think of good examples right now though as at work and commenting quickly), Asiatic lion (as mismanagement of purebred stock somewhat an odd one out), leopard ssp. (save for Amur leopard and these are making a comeback more or less so due to heavy imports from European collections), pygmy hippo, babirusa, anoa and a good number of hoofstock.
Particularly, the private sector and ranching fraternity in later days has taken on many of these phase outs for an apparent lack of interest among the traditional ex situ conservation breeding zoo community. Painful examples are some of the aridland antelope and gazelle (f.i. goitred springs to mind and quite recently another on phase out with 1-2 holders only, but pretty endangered in situ) and f.i. Persian onager and Turkmen kulan. Save for the latter two the private sector has pretty much taken over management of the more common species (allthough quite a lot of the time with herd management tactics rather than actual monitored selective conservation breeding for population and sustainability management.
What is particularly worrying is that even the CSC2 collections and big rangeland zoos within AZA are adopting these policies for fear perhaps of being kicked out of the organisation otherwise. Breeding f.i. of Soemmerring's (curtailing breeding) and red fronted (phase out) and earlier Persian goitred (phased out already).