Ghh, must... contain myself... not to start ranting...
As a player of Tomb Kings, poison rules have always made me flinch. I haven't heard the holy water explanation before, but I think it's really bad. That would necessitate that skeletons are unholy. Maybe that is the case with the Vampire Counts' skeletons that are raised against their will as mindless automatons, but skeletons of the TK are loyal followers of their dead kings with their very souls bound back to their bodies cleaned of flesh. And then you have constructs of the Tomb Kings. How can you poison a living statue? Popular argument on that is that poison is not really poison but acid... That would make all the poison carrying creatures have at least three different types of poison? I can see Dark Elves doing that. And maybe Skinks get their poison from Poison Acid Frogs that they bless before going to war? And then, as an icing on a cake, Ogres have models that are Immune to Poison. Why? Because they have eaten so much all kinds of stuff that they have become immune...
Sorry about that, I know it's fluff and that the rules are not perfect, and I do accept them, but it sure does feel good to vent sometimes. Also, sorry for the further derailment of the thread.