Rewind your memory too and dumb that brainwashed material. The generals have no choice because your leader Mujib traitor had the entire plan setup already in 1970 in Tripura and agartala. Your Mujib traitor presented tons of demands in sort of points, some points were negotiable but others were outright treason. Still Pakistan send several officials for negotiations. Your Mujib then use his second part of plan and started instigating youth of Bangladesh and history tells us, when a population start rising there is bloodshed and so that happened, once Pakistani forces tried to stop those youths and in that process even used deadly force, your Mujib advertised that as Pakistan's oppression on Bangladesh. What happened afterwards is all known.
So don't just blame Bhutto as your own leader Mujib was involved in a much bigger game than Bhutto could ever imagine. Bhutto was inexperienced and if Mujib was honest, he would've pushed for negotiations, but his sole aim was to work on Indian interests and to make Bangladeshi people believe that independence is what was needed.