Because apne are total food-oos. This law didn't effect Indian muslims in any way, so I don't know why they threw a hissy fit. It just prioritised Hindu and Sikh refugees from places like Afghanistan and Pakistan. Nehru and Gandhi really did mess up big time allowing so many suls to stay behind after partition. Tara Singh for all his failures did at least help get rid of them from Punjab.
Can you imagine suls in Pakistan protesting if only muslim refugees were allowed into their country?
What makes it worse is how these Punjabi women dance these days, mimicking the men with their hands in the air, stomping their feet on the ground. At least the giddha from back in the day had some feminine qualities to it.