As you say, this is only one point of view...
The main idea behind the argument that India carried out a conspiracy focuses on the role of the Hindus who were living in East Pakistan at the time. It is claimed that they (with the help of India) incited a desire to split among the other people of East Pakistan.
The East Pakistanis were already feeling unhappy with their status because they felt that the West was favored by the government even though the East was providing a great deal of the country's economy.
The claim is that India and the East Pakistani Hindus exploited this discontent and fanned it into a split between the two parts of the country.
Conspiracy implies tings done in ways that involves secret actions taken someone. There was no scope of such roles being played by India. The events that led to East Pakistan separating from from the West Pakistan to form Independent Bangladesh started the highly unjust and oppressive treatment meted out to East Pakistan when it was a a part of Pakistan. This oppression of East Pakistan as well as the growing resentment of Bangladeshi people and their demand for fairer treatment were all open activities> So was the open revolt by Bangladeshi people after their leader was arrested and kept in prison in West Pakistan. India could have in no way secretly encouraged the West Pakistan dominated government to try to crush the popular movement of Bangladeshi, who were till that time Pakistani citizens, by military might.
India got involved in the struggle of Bangladeshi people only after they revolted openly against Pakistan, and when India joined hands with Bangladesh to defeat the Pakistan army, it was an open war and not a conspiracy.
Most certainly India helped Bangladesh to free itself from the clutches of oppressive Pakistan rule. But it was an open help. There was no conspiracy.
I think the comment made by Pohnpei in answer above contains some very confused statements. First, the Hindus in Bangladeshi are Bangladeshis. Second, the Hindus in Bangladesh did not take any lead in Bangladesh struggle for separation from Pakistan. This struggle was completely led by Muslims. I am sure Hindus must have played a role like any other common people in Bangladesh. But nothing beyond that.
I'll suggest you to think and criticise from an objective view first, then to think as a Pakistani.
Anyway the answer to your question is, India was not a conspirator at all. The then East Pakistan's leader Sheikh Mujibur Rahman asked for Indian government's help in order to give shelter to the millions of refugees, to give proper training to his men (since East Pakistan did not have that much well trained army-power at that time), and above all, to help them directly in the battle-field. India might have had a strategy of her own to fight against the West Pakistan, but it was not something conspiratorial. Remember, helping somebody who is your enemy's enemy means helping your friend.
And, please, research well before being driven to such bias blindly. Sometimes, people ignore the mistakes their own country makes, which is very shameful for the national identity. You'd better look through the following links.