because people are bigoted and racist?
Not necessarily. People tend to feel more comfortable around their own class or ethnicity - just seems to be the way it is, almost instinctive. Once an immigrant population is established in an area, it's natural for newcomers of the same origin to move into the same area so that they feel "settled" more quickly rather than being the odd one out in an almost exclusively white community. It works both ways.
I don't mind where I live at the moment, there's a reasonable mix and there's not really much trouble as the large majority of immigrants here integrate and talk to everyone else.
However, there would be a tipping point. If I was walking around the streets and never heard a single word of English spoken, I think I'd feel quite uncomfortable and would probably move away. Simple as that.
To many, I'm sure it's about feeling at "home"; when the demographic changes so rapidly that you no longer recognise your home town and social cohesion disentigrates, then there's something wrong - I don't agree with the view that we should just bend over and take it.



