This is all unsubstantiated, as I think you'd guess. However, apparently the recent hostilities have virtually destroyed Gaza Zoo. The London Times has a slightly less inflamatory version.
Unfortunately, in any human conflict like this, zoos are always badly hit, because they require people to take care of their animal charges. Zoos need staffers to look after the animals, constant supplies of food, clean water to clean enclosures and for drinking water for animals. When human conflict disrupts the flows of any of that to a zoo, it's the animals who suffer.
And the animals did nothing wrong.