The whole thing started back when Jinnah declared Urdu as the national language recognizing the fact that Urdu was the only language spoken and understood throughout united Pakistan. Soon after his speech, the Bengalis recorded their protest and demanded that Bengali should also be made the national language while totally ignoring the fact that unlike Urdu, only handful of West Pakistanis could communicate in Bengali. This hyper-nationalistic view did not help the relations of East and West Pakistan and right from the very beginning, East Pakistanis lost sort of confidence among the West Pakistanis. Mind you that Pakistan had just come into being and fighting on petty issues such as national language was not perceived as good gesture on behalf of the Bengalis.
A lot of problems could have been avoided by simply granting the East Pakistan provincial autonomy but alas, it could not happen due to the shortsightedness of our leaders including Mr. Liaquat Ali Khan.
1. It was a forced decision to make Urdu the national language of East Pakistan. And contrary to what you say, Urdu was never a language which was known to the East Pakistanis. This was socially, culturally and politically impossible. There was no doubt that Urdu alone cannot be the language of the Dominion of Pakistan.
And the resolve of Mr Jinnah at the Jagannath Hall of the Dacca University stating that Urdu and Urdu alone is going to be the language of united Pakistan, nothing could hsve been more potentially disastrous.
Urdu till today is not widely written, spoken or understood in B'desh let alone between 50s and the 70s. There was no fact, other than uber nationalism propounded by Mr Jinnah to forego the language spoken by the majority of United Pakistan.
2. The voice of the Bengalis was complete moderation. They did not demand anything like replace Urdu with Bengali, but they wanted that both these languages be made the official languages of Pakistan and not the language of the elites - Urdu. You should have taken into consideration the moderate demand.
3. Even if the West Pakistanis could not comprehend Bengali you should have said that okay
"For all official communication in East Pak it is going to be Bengali and in West Pak it is going to be Urdu and during cross cultural/national level discussions we stick to English", it was very simple...
4. Even after so many years you have not realised that the ghetto that was created for Bengali and the speakers were the main reason behind this. The Bengalis worked and lived in silos it is as simple as that. And talking about nationalism it hasnt served your purpose even after so many years.
Bengalis were, are and will forever be nationalistic, as they have a culture (transcending religion mind you!!!) and a great history or literature and architecture and it was no way possible that you become blind to this and start propagating something which is self-serving and still got away with that.
There was a price to be paid and it was paid in full.
Thank you very much