Firstly, can this notion be proved with solid reasoning or any empirical data? I suppose not. Who are proponents of this claim? Besides few racist morons, no one else. Can you or any other supporter of this claim tell me that how Jutts of Punjab and Wazirs of Frontier are related to each other? How Muhajirs of Karachi and Murris of Balochistan are related to each other? How Sindhis and Kashmiris of Punjab are related to each other? And let's suppose they are related, then why Muhajirs are killing Pathans in Karachi? If they are from the same stock then why they dont recognize it themselves? Why their ethnic leaders hate each other? Tell me a name of any ethnic leader who recognize this so called fact. Does ANP, MQM, PTM and BLA recognize this? No, they dont. All of them hate each other and all of them hate Punjabis. For these reasons, the claim of nationalism based on ethnic distinctiveness is absurd and illogical. I strongly believe that these notions are propagated to break Pakistan on ethnic lines. You should feel happy that some Pakistanis are also living in this lala land. But, believe me they are few and they will not be successful. We will continue to fight Hindu hegemonic designs at all fronts, whatever the cost may be.
To address the issue of Chaudry Rehmat Ali and what was his motives, I am creating another thread.