Now more seriously : WHY ?
Most of the species you list-up would be much more benefit from conservation-plans in their native countries and when western zoos would give some help to such programs, this would be much cheaper and ways more effective then bring these species to western zoos.
Taking animals from the wild almost always mean that you have to deal with losses - even succesfull programms like the Californian condor and the Arabian oryx lost animals in the proces bringing animals into captivity.
In other species the losses are even much bigger and the succes was more limited. Examples are Sumatran rhino and Great blue touraco.
Especialy this last species is very difficult to use to captivity and losses are high as I have experienced myself ( death-rate of almost 50 % ! ) and in the literature even death-rates of 80 to 100 % are mentioned !
For species which already have good captive populations ( Bonobo, Okapi, Malayan tapir ) I can't see why there should be brought in new animals ( which also could bring in diseases ! ).
For some species which are already kept in sanctuaries in their native country and from which some are kept in such numbers that the sanctuaries are somewhat "over-populated" - drill is an example - maybe some "surplus" animals could be brought to western zoos but this are only exeptions.
Also for some island-species it could be a short-time solution to bring some into captivity in western zoos like Durrell has done with a number of species but in general I would say, try to create reserves in the native countries or in the worste case breeding-centres ( a good example for this is the Philippine eagle ).
Of course for us Zoonerds it nice to see ( very ) rare species but what is more important: that we are happy or that the animals are happy ???
Yeah, somehow I partially agree with this statement.
I mostly taught on animals from their native range countries, wich means that they can be imported from sanctuaries as you already mentioned, not directly from the wild, or after some period of adaptation in captivity there.
I know that some species experience great loses and are not successfully bred in captivity, and thus I don't mentioned such animals, like sumatran rhinos, harpy eagles, or shoebills for example.
But some reasons why should be approved additional imports are:
-Bolstering genetic diversity of captive populations (for example, okapi or koala population in Europe will benefit a lot) and thus more longterm survival in captivity.
-More zoos want and deserve to keep animals from species who are not very represented in zoos, like bonobos for example. Why not, some zoos in Spain, Italy, or even some other zoos (like in Balkans), do not get some bonobos. Zoos in Balkans even don't have any two western lowland gorillas (smalest social group, not solitary gorilla- not acceptable) (of wich there are 470 individuals in european zoos).
-Establishing captive population of animal species for wich there is not captive, ex situ conservation, like forest elephants (Loxodonta cyclotis), Javan rhinos, mountain gorillas or Indochinese tigers, and from species that at the same time, should easily adapt to captivity.
-Saving animals from the harsh wilderness because there is high probability that they would be killed by poachers, like the accident in Epulu okapi station in 2012, or poaching of more than 1500 rhinos in Africa last year! Or because of loosing range and rfagmentation of population, so there is not realy much space left for one animal population to expand or for animals to find enough mates.
About transmission of diseases, it is best such imported animals first to be carantined in very isolated places, for example edges (eg. Gibraltar) or islands (eg. greek islands), and alternatives-exceptions to be granted from EU, or trough third non-EU countries.
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