Why do Indians struggle to assimilate abroad?

I have lived in some European countries and what I see is Indians flocking together sort of living a parallel lives to the natives. Moreover, they usually have friend circles of Indians who only speak their language, the most common groups being the Telugu and Tamil speaking Indians. I have also seen sort of racism from fellow Indians based on languages, where they tend to have some supremacy based on their castes and their native Indian state. I see so many posts from people on Reddit who aspire to leave India or who have already left India. I want to ask what's the point of leaving India if you never wanted to assimilate in your new country and wanted to live in parallel societies? Also, why do most Indians tend to hang out with only other Indians who speak same language or are from same state, you could have been better off just staying in your Indian state, Why perpetual and reinforce those stereotypes about Indians not assimilating due to your actions ?