Let me explain: (Especially for those commenting, this isn't history )
So the movie is to teach you the value of Sikhism, and how Ardas can enhance the courage of Sikhs. They're not teaching you the history, they're teaching you what it's like to be a Sikh. Now try to recall what they tell us about Sikhs in the movie.
1. Sikhs protected everyone for the sake of their lives.
2. Sikhs chose freedom and fought against the Mughals rather than being a slave.
3. Sikhs didn't weep over being low on resources and thanked their God for their life before beginning a battle.
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Now you're criticizing the direction and storytelling, you're missing the viewpoint to learn about Sikhism and focused on learning about the "History" of Sikhism.
if you read this, watch the movie to learn about Sikhism, don't go for your history class here and you're gonna love it.