Since your grandparents had left the country 50 years ago, it is no wonder you are unable to connect nor understand your Pakistani Heritage, If you've still left any. It's better for a person like you, who's far removed from it, to not carry it anyway.
What connects me to my heritage is not the unstable and constantly changing politics of the country, but it is the land i was born in, all the places i've lived in, all the people i've met and got along with, and all those things unique to a Pakistani brought up, the culture and what not. It is in the tongue i speak, and perhaps even in my mannerisms.
You clearly don't have any of that and many others do, so there's no point in arguing about it. Just, Perhaps you shouldn't rub your inferiority complex onto other Pakistanis, to which, these things hold a sentimental value.