We all live in a pretty crappy world.
Communities are typically self-organizing.
They start from a small group of persons interested in an ideal, and they grow. However, as they grow, the ideals get smudged and fade. Contention surfaces, and underlying differences in opinion become more apparent. Before you know it, the vast majority of the community is in an uproar. Sometimes, these differences and contentions cause a rift so great in the community, that the community is split asunder, and two independent communities are born.