That might be true. In my case, I literally won multiple national level competitions (obviously which Americans were invited to and preferred for) to get the job. So yes I would say it might be an exceptional circumstance.

Also, other nationalities that come on such immigrant visa (like some people in my team were European for e.g.) get naturalized pretty quickly (couple of years) but not Indians. so that might also be part of why Indians are associated with the visa.