Nonnie these groups exist not to diminish any other group but to give a minority a platform. There is no ban on, for example, Chinese Radio ( I suspect it does exist somewhere!) or on any minority group getting a group together if they feel the need or desire too.
I suppose I just ask why not Asian Radio /Ballet Black etc ? Is it causing any problems for anyone? If not then where is the harm?
As someone from a dual heritage background perhaps I can say why I like to 'celebrate' my non-Englishness specifically. I live in England and the majority of people are white English as is the prevailing culture. (I know there are particular areas where this may not be the case) I can visit places that are quintessentially English quite easily, eat English food, hear English music/language, TV, the whole of England is living English history. I celebrate the Englishness in me on a day to day basis!
There is nothing around me that reflects the 'other' cultural part of me unless I actively seek it out or make it happen for myself. When I cook a traditional meal from my father's cultural heritage to share with friends, play music, share books etc etc I am celebrating my otherness and showing that it is as valuable as my English heritage. I am not ashamed of it nor proud of it..it is just an equally important part of who I am. I don't do it to belittle my Englishness!!