I personally can and have lived in a nation that has Hindu nationalism. I mean my ancestors left India to then (east) Pakistan during partition trusting Jinnah and had to escape that during 71. We arrived as refugees in India. Even in Modi my hope was that being a strong leader he will unite the fractured Hindu populace into a strong mandate and being a business first PM he will push for economic and legal reforms. He has to a non-insignificant extant.
But the amount of polarization and sheer hate that has come out of this process and from him and his own leaders is simply too toxic. Hindu-Nationalism in India has now become a literal synonym for anti-Muslim, anti-Sikh and anti-Christian movement. This was not necessary. This is just stupid. You can have a nation that is based on superiority of one faith and yet gives a tolerant space for other faiths to live peacefully. Nominally, many gulf nations are now Islamic nations but they do not practice anti-other-religion policies.
If he was a nationalist strong man, it would have been fine and perfect too. He and his party is more like "anti-others" first kind of ideology these days.