* Do Sikhs in KPK not speak Pashtu?
Lastly, i don't think matters. You see yourself as a Pakistani, Pashtun living in the UK. Does that mean you should only be allowed to live in your place of origin?
Similarly, the Sikhs see themselves as Punjabis not in the aspect of 'race' but religion since the Granth Sahib which is their holy text is written in Punjabi and all of their Holiest places are in Indian Punjab, some in Hassan Abdal.
Just as reading the Arabic to be able to recite the Holy Quran, doesn't make you and me an 'Arab', similarly it doesn't make the Sikhs in KPK, Afghanistan or any other country for that matter a Punjabi.
Punjabi is a language, not a race. Inhabitants of Punjab on both sides are not the same people nor all Punjabi speakers, speak the same language.
In the end all of us are childern of Adam and Hawa (PBUT) who have migrated throughought ages for nomadic instinct is human nature. None of us are 'native' to any particular geography.