This is not an exhaustive explanation and will no doubt evolve as time goes on. We found that we could no longer support being part of an organizational structure that was not supported in the scriptures. This just does not exist in the New Testament, where believers gathered in homes in smallish groups and shared their life and faith with one another face to face.
Some groups are a bit large for the average living room and so gather in a hall or some such.
They don't call the building a church, however. All are free, and encouraged to take part in the proceedings. This leads to another reason some of us are in home churches. Many of us over the years found that the established churches simply could not offer us real relationships and connectedness with other believers. All this because we simply wanted the opportunity to share with our brothers and sisters something of what the Lord was showing us or doing in our lives.