Yeah, that's true. Point taken, but still. At least they should consider blessed terrain hazardous. They don't consider poison hazardous any more but non-zombie characters don't walk into anything that's bad for them.
Hopefully the undead NPC will bleed poison then.
Someone else, I forget who, said something clever on this matter. I will paraphrase:
Because they are not ACTUALLY zombies. They are not ACTUALLY undead, "Zombie" is just the name of the Talent. Just like taking the Demon Talent does not make your eyes glow and scales punch out of your back, or the Ice King Talent does not make a crown of ice appear on your head.