Owning a venomous pet is already an expensive liability waiting to happen, or death. I think it's irresponsible to own one as a pet in the first place. I think it's equally irresponsible for an owner to not protect themselves or anyone else who might get bit by their animal (aka having antivenom). They took on the animal, they should have taken the expenses and challenges into account before getting it.
I don't know if that hypothetical situation could be true so I can't say I feel anything about it.