Depends how you look at this and how you look at the Pakistani identity.
Identities are formed through existence of a community over centuries.
Our identity was always Indian, but for some reason people take offense in this. Infact, alot of brit pakistanis on this forum get offended by this aswell.
So our heroes were those people that were born here and lived in these part of the lands. People like Ganga Ram, Har Gobind Khurana, Dilip Kumar, Amrish Puri etc, should be recognized as Pakistani heroes as they born in our part of the land.
But the issue always was that we were bothered and non accepting of our Indian identity. So, to counter this, we have been focused on making a Pakistani identity. The Pakistani identity is basically anyone who is a Muslim and only follows shia or sunni sect, is considered a part of the Pakistani identity.
To enhance this identity, you will notice all the soo called heroes of Pakistan are only the muslim conquerors before 16th century. So basically what we have done is deleted all the hindus and sikhs, and choose all the muslims warriors who landed in British India, not mattering where they landed in Mumbai, were from Afghanistan, Tajikistan or Arab, and we basically placed them in our history books and claimed him as our.
For example, some random guy from the 7th century called Muhammad Bin Qasim is the unofficial Abu of Pakistan, only because he as a muslim landed in Sindh. Even Bin Qasim wouldnt had figured that 1400 years later he would be recognized as the father of some random nation, only because that nation wanted to associate itself with muslims only. Our history lessons start from Muhammad Bin Qasim.
And than, when the Pakistan movement is discussed, again, only the muslims are seperated. Meanwhile someone like Jogendra Nath is a forgotten side note.
All this is not a mistake, it has been done on purpose, just to show that Pakistan is a Muslim state only and is made for Muslims. To further enhance this image, all our missiles have been named after past warriors and conquerors, like we have missile called Babur, have a tank called Khalid, only cause Khalid Bin waleed existed in Makkah back in the 6th century.
So, what the person in op said is true, and basically we ended up cornering ourselves into that position. Its not just Punjab Pakistan, but overall whole Pakistan has done this.
However, this is where i appreciate Maryam Nawaz, as Maryam is trying to enhance Punjabi Culture, and in her effort she has tried to enhance the language, aswell as recognize the non muslim heroes of Punjab aswell. However, it will take a massive effort, along with the eradication of groups like TLP and other religious terrorist groups that go crazy when a non muslim is recognized in Punjab.
Its quite interesting to see this change from Maryam Nawaz, considering how her party was formed through using religion and promoting groups like Wahabis and Deobandis who in past had a religious hold on the public. This is the beauty of democracy, as in democracy, even political parties start to transition and adapt to modern world.