Even if such a definition had any validity, the group was voluntary and was small enough that individual accountability was immediately enforceable. Deviation from the contract once signed was punished by death (effectively). In addition, failure to sign on didn't have a group hunting you down and punishing you. As a final note, those groups were temporary -- a means to an end at which point the individual family unit again reigned supreme.

To be comparable with the common political view, every person would have to agree to join, he arrangement would be temporary, the punishment for violation would be death, and choosing not to join would not be a disadvantage.