If you've seen the movie Blackfish, you might be outraged at the treatment of captive orcas and have a strong anti-SeaWorld sentiment. However, if you've never visited the park for yourself, I urge you to visit it before you finalize your opinion.
Blackfish does make some valid points, like the horrible way in which orcas were captured in the 1980s and the abuse suffered by Tilikum at his first home in Canada. Unfortunately, it also misrepresents and sensationalizes a lot of information.
I don't support the capture of any more wild sea creatures for marine parks. However, I accept the reality that there are many currently in captivity who were caught back in the day. While releasing them into the wild is a romantic-sounding notion, it's not at all realistic. That's especially true when given that most orcas now were born in captivity and have spent their whole lives in the care of humans in a limited environment. Thus, I support SeaWorld Orlando as a place that cares for the animals in collection as well as possible in captivity and a park that puts some of its profits into important rescue work.
You may or may not agree with that viewpoint, but check out this list of five seasons to visit the park before you make your final judgment. Then, whatever you ultimately decide, you opinion will be based on facts from both sides rather than a single dramatized-to-maximize-outrage-and-profits movie.