Iguanas already have a bad rap. Why increase the negativity? Viewers learn new things by sound-bites. By broad-brush generalizations. Even if the film states that bites are rare, people will naturally believe that bites are common.
Then again, since most iguana owners have no idea of how to care for them, make a film that magnifies all the negatives about captive iguanas. Maybe then their popularity will plunge.