The original question had to be edited. I would suggest that one reason why humans are presented as a social group is that the humans represent where the clones wish to be. The clones, as a group, wish to emulate and become humans. In presenting the humans as a social group, the clones perceive them to be powerful. This is where Ruth, for example, directs her efforts in wanting to work in an "office building." She wishes her life to closely resemble the social group of the humans. The belief is that if they can display the same social traits as humans then, perhaps, the life of a clone will not reduced to being harvested and annihilated. Humans are presented as a social group to also display the power they have over the clones. The notion of solidarity in human consciousness is enhanced with the manner in which human beings are shown to be a social unit. This form of unity is distinctly different from the clones, who are harvested as isolated beings, devoid of any social group that represents or assists them. It is through presenting the humans as a social group, that their power and allure over the clones becomes more evident.