That's not what is actually happening, and is a very common incorrect characterization by progressive/Western groups/others. India's Citizenship Amendment Act (CAA) grants refugee status and paths to citizenship for refugees from some of the surrounding countries, but only if they belong to certain persecuted groups. If you're a Muslim from a Muslim-majority country, then almost always you are not a refugee escaping persecution. In fact Pakistan, Bangladesh, and Afghanistan all have Islam as their official state religion. So why would you be given the same refugee status and path to citizenship in India?
You have to also keep in mind, when you're asking for nationalism to take the form of unification, to Hindus in India that sounds like asking victims to accommodate their oppressors, given hundreds of years of invasions and brutal occupation of India by Islamic powers and then Western colonial powers. The push from Western actors like America to push for a secular India is equivalent to saying "indigenous people in America need to make way for the occupiers that perpetrated their genocide".