Board Thread:General Discussion/@comment-4444715-20170215042751/@comment-25936766-20170215045259

Because:

1) The internet went down that day, meaning the other kingdoms could only have local-level communication. No one knew what happened in Vale except for small bits, leading to:

2) One of the few things people actually managed to see, thanks to Cinder recording the thing, was Atlesian Knights shooting everyone. And since there were witnesses as well, people present in Vale at the time who saw the AKs shooting at the civilians and destroying Vale alongside the Grimm and the White Fang.

Considering Atlas, via Ironwood, basically sent their army there without any warnings or heads-up, supposedly for their "protection".....well, do the math.