Most effects that grant a protection ability do so by specifically stating what quality is being protected against; for example, protection from red, protection from artifacts, or protection from Goblins. Spare from Evil is a bit odd in that it grants creatures you control protection from creatures that are not human. In most cases, this is easy to understand, but there is a slight wrinkle.
Creatures that are both human and some other creature type are human. In other words, they are not non-human. For example, if you control a Chapel Geist and have resolved Spare from Evil, it will have protection from non-humans. However, this Chapel Geist can be blocked by an Insectile Aberration. The Aberration in an insect, but it also has the creature subtype of Human and therefore it is not a non-human. This Insectile Aberration will also deal combat damage to the Chapel Geist because of this. Similarly, this Chapel Geist can be targeted by the activated ability of a Daybreak Ranger. The fact that the Ranger is also an Archer and Werewolf does not matter.
When you want to know if something is non-human, you just ask “is it human?” If the answer is “yes,” then it can’t be non-human.