I don't think you should be going to Seaworld.
The Killer Whales should not be kept in captivity full stop.
We as humans should be happy just to view them from their natural habitat.
I am not sure whether the video you were shown was genuine, there are lots of supposed 'real' attacks available online.
The general consensus of why the whales behave the way you see in 'attacking trainers' if you do a little bit of research is that due to the conditions they are kept in, and the things that they are 'conditioned'/'made' (call it what you will) to do, repeatedly, is that they are effectively insane.
What they are made to do, and the small pens/pools whatever they are kept in, are so far moved from what should be their reality, that they are slowly going mad.
This is a bit 'weird' for me, as only the other night I was looking up to see what had happened to Tilikum who was the male whale involved in the most recent 'attack'.
Did you know that in the year since the attack, he has been kept alone, and without virtually any contact between him and other whales or the trainers ?
He has started 'performing' in shows again, but gets no praise or 'reward' from trainers for that, only massages with huge jet hoses, when he previously had regular one-to-one contact.
SeaWorld deny this, but previous and current members of staff appear to clarify the lack of contact.
This site makes for upsetting reading : www.orcahome.de
Click on 'orcas in captivity', scroll down and then click on 'violent incidents between humans and orcas'. There is a very good article if you then scroll down to No. 55 and click on the 'Outside Magazine' link.
I would like to see a ban on Killer Whales being kept in captitvity.