Neckbeardism exists in the frission between being a social outcast, and a desire to fit in or belong to something. Tribalism and the desire for social acceptance are strong urges. Being alone for long stretches of time tends to lead to mental health issues.
So, you have these kids who perhaps don’t have a good relationship with their families. Maybe they came from broken homes, or came from families where they were somewhat ignored. They grew up shy, or otherwise isolated.