I don't know man...why is it that only Urdu-Speakers in Karachi in Sindh call themselves "Muhajir"? Is it because no Muhajir ever went/lived in Punjab KPK or elsewhere?
Nope, it's because the "Mohajir" in Punjab have integrated into Punjab and call themselves Punjabi, weather they speak Punjabi or not. Neither do we "Purana Punjabis" have any problems with it, neither do they.
So I ask you, why don't you drop your racism and just call your self Sindhi? After all, Sindhi people themselves are named after Sindh "the province of Sindh-River". You don't have to be Sindhi by blood to call yourself that, just like you don't have to be born to Punjabi parents to be one.
You guys are Purposefully creating a separate identity for yourselves, then use this identity to claim superiority over others and cry they're being "racist" towards you. Your own attitude is part of the problem here.