I gotta ask, what's so wrong with a pluralistic system of worship if it's teaching peace, and not to hate another denomination?
First off, I'd just say sorry for the bad experiences. Seems crazy that such churches like that exist but apparently they do. Anyway, I don't think there's anything wrong with having a pluralistic system that advocates world peace, educations, etc..
But I just don't see how Buddhist, Muslims, Christians, Athiests, Pagans, and other religions, can worship God in a unified manner. They are all doctrinally different and even though you may have many different denominations within Christianity, at least the core content should be the same (ie. saved by grace through faith). Jesus' teachings about the way to eternal life were exclusivistic.
Jesus might say: You don't get to the Father (eternal life) through Buddha, Mohammed, the many Hindu gods, fertility goddesses, or your own merit. You get it through me.
So I believe that mankind regardless of your belief system can fight for peace, world hunger, AIDS prevention, and other world issues, but I think that's where the line stops and once you step into the realm of religion is when serious questions need to start being asked. Hopefully I touched on the what you were looking for. If not, sorry