I resisted getting into this intra-Indian debate.
However I see so much "misinformation" being spread around. So here are my 2 cents worth
Congress was not 100% secular. Instead it was "multi-religious" platform. All major Mullahs were in Congress
--- Main funders for Congress were Textile Mill owners
--- Thus it was a party for the mill owners by the mill owners
Muslim League was not 100% religious either. Majority of Mullahs hated Jinnah and declared him Kafir.
--- Main funders for ML were big land lords
--- thus it was a party for the land lords by the land lords
With this quick bullet points,
Let me emphasize that religion was being used by both parties to gather more votes. Congress used Mullahs to gather Muslims votes, Mandirs to gather Hindu upper caste vote, and Harijan slogan was used to gather lower caste votes.
But the real fight was between the old aristocratic land lords (mostly Muslims)
and
Newly rich textile mill owners that were mostly Hindus.
Therefore the core of the tussle was economic.
and lot less religious.
Thank you