There are no perfect citizens, nowhere in the world, it is enforcement of law that makes one behave. Law enforcement has gradually vanished from Pakistanis cities (it did exist once) and the result is in front of you. However, unlike rest of Pakistan that at-least started out with law enforcement, FATA never had any writ of the government, they never allowed it.
Please do not put all the blame on one ethnicity that is 50% of the total population of Karachi. All sorts of ethnicities call Karachi their home, not to mention Afghan, Indian, Bangladeshi, Burmese refugees, and have fair share in turning the city into a shit hole.
I am trying to understand your point, you also try to see where I am coming from. You are talking to me as if I am Karachite and MQMer whereas I have hardly lived there for one or two years, a time when I was teaching in Aga Khan university, and left to States afterwards.