Have any zoophile organizations sought an alliance with us?
While I don't see the point in human-animal sex being illegal, I don't see us being natural allies with zoophiles either - at least no more than we should be natural allies with any other category of human being.
I'm sure that someone could come up with a list of notable zoophiles in history, especially as some ancient religions required ceremonial copulation between human leaders and horses, for example, but that isn't really the point. An attraction to juveniles and juvenile characteristics is at the root of what it means to be human, seeing as humans are neotenous apes. Pedophilia therefore appears to be linked to the plasticity of mind that is crucial to human intelligence, and to the reduced aggression in adulthood which is crucial to human civilization. In short, there is no humanity without pedophilia. So where exactly is the benefit for us in such an alliance?