To say that two Indians are more dissimilar than two people from different countries is a ridiculous argument. You have no idea if both those Indians are Parsi and share extremely similar cultures even if their language is different, or if the German is Turkish-descent Muslim and the Swede is a Nordic Buddhist. You are assuming the Europeans are more similar based on what? Sweden and Germany have vastly different understandings of the role of the State, different religious practices even within same/similar religions, different food.

There is a crazy amount of diversity in India, but not nearly as much as in America or Singapore or any other immigrant-accesible country. India is pretty shit about giving citizenship to other nationalities (they even strip their own citizens of their nationality if they are the "wrong type" of Indian based on BJP bs), Indian residency is basically only possible if you are of Indian descent. For a country of over a billion, India has 5.3 million immigrants, while Germany, a country of 83 million people, has over 12 million legal immigrants.