Hindus anywhere in the world will naturally be more loyal to India than their country of origin just like jews will be more loyal to stolen land of palestine.
Not just the Hindus; us and other sister communities as well. Our history started in these lands and naturally we will prefer it that way
You idea is good but we don't have sufficient land for all the Hindus around the world. Besides, until we change the constitution to a Dharmic one, we cannot officially claim to be the "zion" of Hindus, Buddhists, Sikhs etc.
Besides, if this is to happen then two things would take place:
1- Migration of non-Dharmic communities to their countries of choice.
OR
2- Joining up of many Southeast countries with India due to shared culture and faith.
Even if this were to happen
hypothetically, it would be a real headache to re-adjust our entire finances and national economic structure as there would be a lot of brain drain and reverse brain drain. Accommodating economies and liabilities of half a dozen more countries would be a big crunch on our resources EVEN if their lands join us. This will lead to an extremely chaotic situation.
So in short, it is worth too much trouble even if a population exchange is agreed upon.
The only difference is that hindus have legal and historical claim to India where as Jews have a mythical claim to Palestine. It makes more sense for India to give citizenship to fellow hindus from anywhere in the world.
First off, we need equal amount of land to be able to accommodate more Dharmic followers. We aren't exactly Russia in size to accommodate every single believer of Dharmic faiths.
Secondly, would you accept a population exchange similar to how Greece and Turkey had?
You yourself are constrained off land.
Doesn't seem practical.
BTW, Jews existed there long before your community ever was born. So they have full legitimacy in claiming the State of Israel. It was a Jewish kingdom much before both Islam and even Christianity existed.