Simplest explanation is that the card's text refers strictly to the elements of Death and Darkness, which in turn means the creatures. The player is referred to as an elementalist, a wielder of the elements if you will. But because the player only controls the element, he/she does not become the element and will not be harmed by the said card.
That's the thing. Cards, when referring only to the creatures, will say so, like "Freeze the
target creature" in freeze or "inflict 1 damage per round to a
target creature" in virus. Holy light just says target (like fire bolt or ice bolt) in the first part, which is correct, because it can target both the creatures and the players, but it also says target in the second part "If the
target’s element is death or darkness, damage is dealt instead." I think it should be changed to "If the target creature’s element is death or darkness, damage is dealt instead." to avoid confusion.
