Democracy is by it's very nature vote bank politics.
Democracy is for the people as reprsented by the MPs.
Who are politicians ? The person who is chosen by the peoples in a constituency. He will always defend the interest of his constituency or the caste or the religion or whatever sub part he is representing.
Democracy is for the people = Peoples aspirations as reprsented by the MPs who will then formula laws to fulfills those aspirations.
In a diverse country there are bound to be clash of interests.
If I were an OBC i will support the MP only if he supports my causes.
If I am a muslim I will support the muslim friendly MP.