You didn't answer my question.
Also have you ever seen anyone from anyother place whinging about whos living in their area? I am Pukhtoon and a 3rd generation Karachitte and i am proud of both. My family moved to Karachi way before Pakistan was formed, but all my life i encountered people like you who told me to go back to Peshawar. Like other Pukhtoon families, my family was always harassed by MQM goons and then ANP came in to take advantage of this but me and none from my family wanted anything to do with them because we don't believe in spreading division among the people. But people like you always cry about being discriminated against and that everyone hates you. Its true everyone hates people like you but not because of your background but because of your constant rona dhona, especially against interior Sindh. Majority of Karachites have never been to interior Sindh, but i have and i can tell you Karachi is a Janat as compared to Interior Sindh.
As for why people are settling in Karachi? Well last time i checked, Karachi was part of Pakistan and if so Pakistanis are settling in another Pakistani city, whats wrong with that? You can move to Lahore, Islamabad, Multan, Quetta etc etc whos stopping you?
And this is for everyone else who is whinging about Karachi. Try make a difference yourself instead of waiting for someone else to come and fix your problems. The best example is Alamgir Khan from Fixit. He made a difference on his own. There is a famous saying, "when there's a will there's a way"