One of the things that makes US reasearch strong is the ability of it's universities to attract te best and brightest from all around the world. This is nothing new - it has always been thus - though perhals this is incresingly so as the state of secondary education seems to be in decline compared to opter parts of the world.
When researchers stop coming to the US, the state of
research there will go into rapid decline.The US isn't alone though - it's the same story in Australia too.
Given the already established centres for excellence in the US, it's a favoured destination for smart and motivated people from India and Asia, as well as other parts of the world to further their education and opportunities.
Half the world's population is Asian or India/Bangadesh/Pakistan, so naturally you are going to see many from those regions. Be glad for it - or they would be busy innovationg wherever they came from instead of the US.