Anne, sorry to hear you were one of those runners. I can't imagine that feeling of told after getting through 20 miles in tough conditions that it was all for nothing. I'm sure frustrating beyond belief barely begins to describe it.
I know enough of the RD up there to know that it was surely a tough decision for him to make. It sounded like the emergency services were stretched to the max already. Given that, it was probably the right choice but still a very difficult one for runners like you to be forced to accept.