Why are there 2 of each award in left 4 dead 2

if by award you mean the avatar clothing awards. then there are 2 of each besides the health pack (given after finishing all campaigns on any difficulty) which are awarded depending on the sex of your avatar (guys unlock one version of the shirt were as the girls will unlock the same shirt just in a more feminine pose)
so basically there are 2 of each, one for the guys and one for the girls.