Your view of what happened in East Pakistan is just a bit warped.
The reality was very different than what we have been sold and many even in Pakistan buy. Yes Bengalis should have gotten more rights, but that does not mean you take up arms against your countrymen and align with an enemy state.
Also we keep saying what we did to the Bengalis. I once had a Bengali guy say to me that Quaid should have done more after partition. That is how warped their views are. A man who died 11 months after partition should have somehow done more. And 23 years after independence was long enough for their patience to run out, before they went on a rampage killing over a 100,000 (some say nearly 500,000) West Pakistanis, Biharis, and Urdu speaking people. Not to mention murder in cold blood their brother-men in arms and their families.
The killings, murder and mayhem had begun well before any army action. For nearly a month the army stayed in their barracks while Bengalis went on a genocidal rampage killing complete villages and small towns. That news and bodies were never brought to West Pakistan for fear of attacks on West Pakistan based Bengalis. Yet we are the idiots who are made to feel like we did something wrong. The lack of historical record keeping allows these false narratives and stories to perpetuate and here too I will blame West Pakistan. West Pakistanis are too simple to understand the mind and manners of the Chanakya mindset.
This apologetic view of our history is wrong.
Yes there were mistakes, both at a political and military level. But the notion that only one party carries the majority of the blame and that party is Pakistan is wrong.
India worked this division from day one, and drove Bengalis through her propaganda to despise any rapprochement between two people of the same nation. From the language riots in 1948 they never wanted any sense of alignment, and India worked slowly and patiently over the years to drive a bigger wedge. Today Bangladesh is a colony of India no matter how great the GDP is, everyone even in Bangladesh will tell you we live with that weight on us. I wish Bangladesh the best and her people, but I for one as a Pakistani will never forget or forgive them for what they did to our nation.
We'll let Allah and the hereafter judge us all.