Whilst the schools do teach the basics about magical creatures and plant life, the teaching ends there. There’s no thought given as to how best to care for the landscape. As for the wars, they are considered unfortunate, embarrassing historical events, not to be discussed yet alone rectified.
It would be possible for the Queen and her senior magical staff to rectify some of the damage done to the Kingdom, but the thought hasn’t occurred to them to do it. Even if it did occur to them, they’d reject the idea as wasting their magical energy. The Fairy Kingdom fails to recognize its own selfishness here. They’ve got more in common with humanity than they care to admit.