There are very wise and very kind-hearted people in this world. People who love animals, who try to improve the world and themselves, who live uprightly. And then there are also child rapists, and serial killers. Now, that's the situation with the Demons and the enemy entities as well. Demons are the highest point of existence, while enemy beings are the most vile creatures you can think of. Just as the existence of a serial killer does not cast a shadow on a kind-hearted man, the existence of a parasite does not cast a shadow on a Demon.
This is all enemy programming and they are creating systematic destruction and corruption by confusing good and evil. In fact, good and evil are too obvious for the enemy to leave any lasting impression, and while they will meet their end, and in a few years will be driven to absolute extinction, the Demons will continue to shine.