Many former trainers speak in the film. They do have conscience pangs -- they had to believe in what they were doing, and couldn't bite the hand that fed them (figuratively). The company is necessarily mum on the issue. If you work in management in an adversarial situation, you don't have the freedom to speak publicly.
Update: Sept. 10, 2015
Check this article by Alva Hope Rutlin on orca intelligence and social behavior, here. Or this article, "Killer whales are non-human persons", here. Cetaceans (descended from hoofed animals 50 million years ago, when they returned to the ocean for "free fish") have evolved, independently of humans, to about our level of brain power -- a strong case for intelligent life developing elsewhere in the universe. They are the closest thing to "aliens" we know -- and we barely really know how to communicate with them, in any kind of psychological depth.