British army at the time of the two sikh wars in the 1840s consisted mainly of Benagli solidiars, because of the east indian company. When the bengalis revolted against the british in 1857 they wanted to reinstall the mughals in delhi. The punjabis, or the sikhs, neither trusted the mughals nor the bengalis, who they mainly fought against in the two sikh wars only a decade earlier. Thats why they didnt support the "indian" side in the 1857 revolt, as from the sikh perspective that meant supporting one enemy (the bengalis) to reinstall another enemy (the mughals). Indian nation hood didnt exist at that time as it does today.
And this "overrated region" experienced the bulk of invasions for the most of indias history. So excuse us for not being prodictive, bro, we were a little busy fighting invaders.