The nerds have reason to believe that if their community accepts new people, eventually they will be excluded from their own community by the most popular newcomers. That's the whole reason they started their own exclusive community in the first place.
I wouldn't want to live life like a Sentinelese tribesman, I think the uncontacted tribes in Sentinel island would be happier in the long run if they integrated to the global community. But I understand why they don't.