Jim Nash states the bleeding obvious. Excerpt:

You take 32 feet of muscle, teeth and brains out of the ocean, put it in a featureless tank the size of Graceland, force it to act like an idiot in public, and it’ll drown a captor.
…It’s terrible that the trainer was killed, but unless she was less intelligent than the animals she prodded, she knew that keeping orcas captive was wrong and stupid.

It’s a miracle this doesn’t happen more often. I’d like to think there are some whales in Orlando right now saying to each other, “Yeah, he’s a jerk, but Tilikum has a point. Next one that stands on me won’t need shoes ever again.”