The defense she refers to is Maynard's statement after the loss:
"We are heartbroken about losing Harambe, but a child's life was in danger and a quick decision had to be made by our Dangerous Animal Response Team. Our first response was to call the gorillas out of the exhibit. The two females complied, but Harambe did not. It is important to note that with the child still in the exhibit, tranquilizing the 450-pound gorilla was not an option. Tranquilizers do not take effect for several minutes and the child was in imminent danger. On top of that, the impact from the dart could agitate the animal and cause the situation to get much worse."
Goodall's letter continues on to show concern for those suffering in the aftermath: "Anyway, whatever, it is a devastating loss to the zoo, and to the gorillas," Goodall's letter continued. "How did the others react? Are they allowed to see, and express grief, which seems to be so important."
As anger rages against the parents of the boy, the zoo and animal captivity in general, Goodall shows that there's a way to raise a question, while also being compassionate to everyone mourning the loss of a much-beloved individual.