You're only focusing on the negative to be fair. I lived in London, a few different places, some posh, some not. But my fav was I lived in Holloway. It was a busy, bustling place, very multicultural and I really liked the vibe. There were some real characters there too, rented in a huge block of flats and my neighbours from all walks of life & around the world and my neighbours were cracking people. I liked where we lived because it was a nice mix of community spirit without being too nosy and without the small town mentality that sometimes occurs in small towns..!
Yes, was negative, but it's what many ordinnary people there have to suffer on a daily basis. I stopped visiting London on a regular basis in late 80s when it started to get too ethnic. If I go to Warsaw for example, I want to mix with Poles. If everywhere is multi-culti, then everywhere the people are the same - just an international mongrel mix. Mostly made up of those from the more 'problematic' backgrounds.