If, and this is still a big if is some of our minds here, if this world is real then the goblins need to be dealt with as you would any other threat. Applying moral values from our world to this one can only lead to problems. Do you have some idea as to how to get them out of town without killing them? Once they attack they won’t hesitate to kill anyone they can and I’d not like to choose who gets to die before we can react to it.