Didn't know where else to put this, but this has definitely been on my mind lately.
For those that have not seen the film Blackfish, it highlights some of the reasons of why keeping captive killer whales is risky, and some of the behavioral affects it may have on some of the animals, particularly "aggression."
I'd say I'm somewhere in the middle: some of the trainers still have their hearts in the right place, but you're still taking a wild animal from his family and natural habitat.
There's no use in denying that.