There is no such thing as true good or true evil. No such thing as pure black or pure white, there are only varying shades of gray. These are the basic axioms of the real world. There is no such thing as a person or entity which is entirely evil; however, there is no being or entity who cannot conceive of evil. If an evil person can comprehend goodness, there must be at the very least a small amount of good in that person. And if a good person can comprehend evil then there must be at least a small amount of evil in that person. In most people good and evil are weights which balance on a scale. Sometimes the evil is a little heavier than the good and sometimes the good is heavier. The heavier the good side, the better the person is perceived to be. In most cases, the balance changes minimally, whereas a large change occurs slowly over time and can usually be detected. However there are instances in which the scale swings in favor of evil or good without warning. It's not a premeditated act. It's just the nature of humans.
The universe has its own set of scales that swing back and forth like a pendulum. At the opposite ends of the spectrum are magic and technology. *As the pendulum swings to and fro, from eon to eon, so changes the universal laws of nature. It is forever moving back and forth, swinging from magic to technology and back to magic. Onward, ever onward swings the pendulum. Unlike the mechanical pendulum of technology, the pendulum of the universe is slightly erratic in its progress from apex to apex. The amount of time during which magic or technology will be in dominance is unknown.
This is why some ages of technology are able to advance farther than others and why some ages of magic can create and perform more potent magic. The current technological swing of the pendulum allowed for radical advances in technology, thus creating a greater dependence on the marvels of the age. And now that dependence must be severed, as surely as the falling ax must sever the head of the chicken on the chopping block, as the pendulum swings back into the realm of magic. It's not an act of vengeance or retribution for the manner in which technology has mistreated the environment. It's just the nature of the universe.