The actor plays an academic from a Dalit background whose relationship with his mentor, played by Amitabh Bachchan, goes sour when he falls in love with his daughter.
Khan told Mid Day: "I play this guy who is academically a success, so with education comes a certain posture, so that seemed fine.
"But generally speaking, I think you and I will never be able to understand what they have gone through, or have to go through.
"Dalit children still have to clean toilets even while studying in government schools. We have no idea what's happening in some parts of our country."
Khan added that his aristocratic background presented no barrier to playing the role, compared to his "fair skin" and "personality".
Deepika Padukone plays the young woman who is torn between her father's old-fashioned attitudes and her new lover.
Khan also revealed that he was angry at the objections lodged about the movie, which has been passed without any cuts by Indian censors.
"Yes, the subject of the film and the title itself has kind of invited controversies, but since the Censor Board had no issues, I see no reason why there should be objections raised by others? We must respect their judgement," he said.
Director Prakash Jha recently criticised interest groups for asking to view the film before its release in case they found it offensive.