Actually, the amount of chest-beating a group does in indiactive of how insecure the group is over its past, and both indians and Pakistanis do a lot of chest beating. I am merely suggesting that some Pakistanis should avoid being like some Indians in their chauvinism, this would save much embarresment.
If we are really going to be brutally honest, Pakistanis were the people who converted becuase they did not want to face death at the hands of the invaders or were sick and tired of the Hindu caste system. As far as Britain goes, there were no invaders that kick-started the Industrial Revolution or the British Empire, Britain had largely remained the same in terms of composition for hundreds of years preceding these two great events. Pakistanis meanwhile have, much like Indians, managed to do nothing of great value since the Mughals declined.
Loom around the world and see the types of areas where ultranationalism flourishes, places like the Balkans or Turkey where the people are deeply insecure of their past. You can pretend to be proud of a version of history you know to be untrue, but you should at least consider my advice.