Throughout time a rainbow has come to symbolize a lot of causes, groups, etc. A beautiful symbol that represents a spectrum of colors that when combined presents an wondrous display; the way that only nature can do. If you include only the colors that you like and exclude the remainder what do you have, not a rainbow, but your preference. It is only when accepting the whole spectrum of possibilities that you are blessed with an awe inspiring sight.
Likewise, only until humanity is able to recognize the value of their interdependency will we witness the beauty that is contained within.