As I understand it, because the European population has been an ESB from about 2001, but due to many more collections breeding their animals successfully, (as we have seen in the UK since the days when only Woburn seemed able to get theirs to reproduce), changing over to EEP management has enabled better control over this which, in the case of the topic of this thread, would seem to be so.
The argument that much-needed space is required for more endangered suids (Chacoan peccary? Visayan warty pigs?) or for a less inbred bloodline of red river hogs is fine, but the management of one species where no equivalent exists for peccaries or European wild boar suggests to me that the more extreme measures, ie culling, look ineffectual on the wider European captive suid population.
I certainly don't expect all the non-reproductive, ageing babirusa to be culled to make way for healthy young pairs of visayan warty pigs, because they are rare in zoos and the current holders obviously want to hold onto them, which takes the red river hog cull at Edinburgh back to a local decision to cooperate with an EEP recommendation.