I can't find the link to the scientific story I read about this a few weeks ago but they theorized that this was a purely "local" event spurred by one particular "pod" of whales who had been harrassed by fisherman. (if it's accurate)
Having said that, for 90% of the huge steel-hulled ships on the ocean, getting rammed by 50 Orcas might not even be noticed and the whales would most likely be badly injured. And one fisherman with a rifle thinking payback would mean bye-bye Mr Angry-fish nevermind what a bunch of them would mean. (local extinction)
I seriously doubt "kill all humans" is going to end well for whales in any way .... and since whales are pretty smart that means I think the whole story very unlikely.