From Part 2, note the following about the Ahrar: "In their dealings with the Congress, religion was a private affair to them and nationalism their ideology. When they were pitted against the League, their sole consideration was Islam of which they held a monopoly from God, and the League was not only indifferent to but an enemy of Islam."
It suggests that the Ahrar saw the Congress as purely a political party; but the Muslim League as competition in the religious realm.
Of course, the Munir report also says about the Ahrar: "They left the Congress on grounds of religion, and they opposed the Muslim League and Pakistan on that ground."
The grounds for the Ahrar splitting away from the Congress need to be examined.