I'm just saying, it'd be nice to have an option somewhere between "break your paladin oath" and "literally murder 7000 people."
Firts, you can't murder anyone. They are already dead. It's a neccesary condition for being and undead XD
Jokes aside. This is perfectly normal to break oath. In no world a paladin of tha ancients will think as a murder killing any number of undead. They are literally consacrate to end them. It's perfectly fine you think otherwise, but them either roleplay as what a paladin will choose, or roleplay that it's to much at a personal level for your paladin and break your oath and live with it
The broken oath here is perfectly fine lore and logic wise. If you don't like maybe just don't play a paladin, because them what you don't like is the mechanic itself
