Was going to the same thing Andy, " they are beyond the pale" but wasn't sure so looked it up, and your first instincts are correct. It dates from the 14th century when the "Pale" meant a fence or line, to go beyond that mark meant you where traveling into a hostile or savage land. First use actually comes from Ireland when " The English Pale " was used by the English to let people know when they where traveling into uncivilised and lawless lands.
So it pretty much sums the MHanks up to a tee.