I question any documentary that has an agenda before it's even filmed. It appears the entire point of this documentary was to show SeaWorld as awful. Maybe it is, but a good documentary director doesn't make assumptions to begin with.
Have you seen "Blackfish"? I don't think the point of this documentary was solely to paint Sea World as awful. I believe it was fact based. If Your takeaway was that Sea World is an awful place, perhaps it really is.