I genuinely fail to see the concern about white flight. It appears you are suggesting that it matters what colour skin people have, and apply a value judgement to movement of people based on skin colour.
I would certainly rather live in an immigrant community than in some white communities, but the reason has nothing to do with skin colour and everything to do with the people involved. Likewise there are some immigrant heavy communities I don't want to live in, but it isn't because they are immigrants, it's because they share bad behaviour, gang culture etc with the scummy whites in other areas...
As for our culture, lots of things have shaped our culture... Religion plays a big part, but to be honest, the major difference between Islam and Christianity in the west is adherence, because they are both worshipping the same god, with the same basis and similar practices...