Oh wow did it make the news in the US? It is just SO very sad :(
I am not sure at all what happened, I do agree with the theories it could be caused by human intervention. Military sonar is one thing that is thought to cause beachings, but good luck ever getting anyone to admit that was the cause I'd say!!
Who knows, the other theories include climate change due to rising water temperatures and just "an accident" on the whales part, but I don't think for one moment that 2 amazing species can beach themselves by accident!!