Even more specifically, it's a cult.

It has doctrine that makes it look legitimate, but then there are always features that veer away from culture.

It has secret info you can't know unless you are loyal and rank up.

It has rules that separate people from mainstream culture.

It requires missionary zeal that transcends virtue.

It threatens harsh punishments for those who don't contribute to it.

It doesn't allow you to leave without giving up most of what you have.