No system is perfect, on this planet. The reality is that all the large primates are omnivores, as they all eat insects and some eat flesh. They were not vegans, fruitarians, or even vegetarians. Some fruitarians are in denial regarding the above. Some fruitarians try to counter the above with misinformation.
Some conventional vegans have integrity and admit that, biologically, humans are natural omnivores.
Ant-eating behavior of mountain gorillas. The apes that eat meat are perverted. We can accept reality, or live in denial of it. So, I would say that apes eating insects or meat are simply following their instincts. Applying human preconceptions to evaluate the actions of animals can be a tricky matter.