The Hag is part of nature. She is part of the Dark Feywild. Yes, she is a predator, and predators seek prey, always. They seek the weakest in the specifies to prey on always, like all predators do. That prey just happens to be us so we label it evil.
Yet if you are strong, wise, and diplomatic you can coexist with the Hag just fine. The Gur do it because they pass around the wisdom of such things. The Gur are not evil.
The hag clearly isn't part of the nature, she is evil twisted creature, interfering in natural cycles.
How is she interfering in natural cycles? Is decay not part of nature? Is conflict and death not part of nature?
So - everyone is of course familiar with the Cordyceps fungus - which infects and takes over insect host bodies and then takes control of them. What most people don't know is that Cordyceps doesn't actually pass the brain/blood barrier, so the insect brain is unaffected and fully aware of what is going on. It simply takes over the rest of the body directly. Horrific but natural.
However there is a even more disturbing fungus called
Massospora. Massospora infects Cicadas and replaces their genitals with spores, it then hypersexualizes them so it tries to "mate" with and pass on the infection to other Cicadas.
Nature is brutal. Based on this information, how is the hag unnatural?
This kind of hag doesn't protect the forest, but only deform it to her perverted desires
What do humans and dwarves do to forests? Do we not pervert and destroy them to fulfill our desires? Do we not pollute them? How is the Hag different? What actions does she take specifically that are different than this?
Also Hags usually live in swamps, which are important ecosystems.
