I have replied in a general sense, but you must have realised that the point was made in a narrow sense, in the sense that Indira Gandhi's appeals for calm and restraint were brushed aside by Yahya in 1971.
What I can bear testimony to is that
- The Indian leadership was caught by surprise and shocked by Operation Searchlight and its consequences;
- The Indian public, specifically, the West Bengal public, was in turmoil, and felt that Delhi was indifferent to Bengalis being killed;
- The Government of India reacted with great sensitivity and alarm at that frenzy in Bengal, because the state was just then being pulled back from a bloody Naxal rebellion;
- The GoI tried very hard not to complicate a very complicated situation in West Bengal by getting the Pakistani leadership to bottle up the trouble, by giving in to Mujib, not to bring him to the forefront or to win brownie points, but to get a quick end to a problem that was looking really bad. Don't forget that Maulana Bhashani, the leftist-cum-Islamist Bengali leader, was much feared by India, and some people had nightmares thinking that Tiger Siddiqi rather than Mujib would come to represent Bangladesh. In which case, it might have become full-scale counter-insurgency in West Bengal.
I actually saw some of this from the inside.