Many spells and abilities affect creatures in some way or another. When text on a card refers to creatures, it means creatures on the battlefield. This is because creatures only exist when on the battlefield. When a creature card is in any other zone, it is just that: a creature card.
For example, let’s say that you control Honor of the Pure and you have Kemba’s Skyguard in your graveyard. If you cast Corpse Lunge and choose to exile the Kemba’s Skyguard from your graveyard, the Corpse Lunge will only deal two damage. Honor of the Pure will not affect the characteristics of the Skyguard card in your graveyard at all.
Similarly, Grand Abolisher‘s ability prevents other players from using the activated abilities of creatures during the turn of the Abolisher’s controller. If your opponent controls Grand Abolisher, you can still use the ability of a Reassembling Skeleton in your graveyard during his turn. This is because this is an activated ability of a creature card and not a creature.