Yea, well, in my eyes, there's little "United" about a Church were member denominations come and go as they please.
Um they don't tend to come and go when they please. Where the hell did you get that idea. Congregations fall out of communion with their greater denomination all the time. That is very different from an entire denomination leaving, especially since there is no concept of "member" denominations within the church. Those that joined are of the one United Denomination, those that choose to remain separate, did so.
Nearly every denomination has a process for deciding and declaring when a congregation is no longer considered to be upholding which ever tenets they hold to be important. There also have processes and requirements to bring said congregation, or indeed congregations of other denominations, back into the "fold". I think you will simply find that as someone no heavily involved in RL religion, you just don't realise how common this sort of thing can be. Take for example my local Presbyterian church, they currently risk being removed from the register on a simple matter of finance and maintenance of the manse. Should they not perform the maintenance that the State Assembly has deemed is required, they will be officially and independent church and their current minister removed from their service.
When the Churches first united not every congregation wished to be part of the Uniting Church. Thus the Presbyterian split, some joining the Uniting Church, others continuing the Presbyterian Church. It wasn't even the first occurrence of this, The Presbyterian Reformed Church split off from the greater Presbyterian Church several years earlier.
We are talking about the 2nd largest Christian denomination in Australia with some two thousand congregations and a organisation that operates the largest non-government provider of community and social services.
