The province of Punjab lies on the Western edge of India, up against Pakistan, and its people comprise the normal religious mix in India of Hindus, Muslims, Sikhs and other (including Christian) minorities. Punjab, though, is the heartland of the Sikh religion, whose holiest shrine is the Golden Temple in Amritsar.
Sikhs are famous as warriors, and certainly not prone to allowing their religion to be walked on. Remember that not long after she had sent Indian troops into the Golden Temple to break up an occupation there, Prime Minister Indira Gandhi was murdered by her Sikh bodyguards. Not to be messed with, the Sikhs.
All of which is simply to point out that the concept of a "self-hating Sikh" is inconceivable, and therefore any Islamophobes tempted to put this heartening story of religious tolerance and co-operation down to "self-hating Sikhs" or "Hindus in name only" simply show how little they know about religion in India.