We are living in a world which is made of structures. Some structures are made of contents which we know as atoms and other structures that we make after becoming collective atoms i.e. the body of the self are called social structures. We, human beings are part of physical structure as well as social structure.
While creating these structures we always include something and exclude something. In the case of physical structure we include atoms and exclude the space or the void and therefore our bodies are visible. Whereas these physical or body structures are not political. It is the social structures which are political because birth is an accident whereas social structures are consciously created to include and exclude others and this is essentially political.
Social structures are created by including few individuals or a group of individuals and the rest of the individuals or group of individuals are excluded, for instance, family, marriage, friendship, football team etc. These relationships identify themselves as inclusive of the structure and rest of the world is excluded. For example, A, B, C are a family 1 and X, Y, Z are family 2, both the families are based on these premise of inclusion and exclusion. The members of the either of the family cannot become part of the vice versa family.
This is one of the reasons that social structures are discriminatory because they include some and exclude some on the bases of their interests and by doing so they give birth to injustice. Any structure in order to have a larger periphery of justice should be inclusive and thereby it can cause a feeling of affiliation among the members of the world society.