I know you did not mention cults, but someone did.

I did, the Jehovah's Witnesses have many of the characteristics of a cult mainly,

Members are strongly persuaded to only associate with others in the religion to avoid 'contamination'.

Once in the grip of the cult it is difficult to leave as it will mean the loss of friends and on many occasions other family members who will actively shun the apostate.

There is a lot of secrecy higher up in the ranks who still give protection to child abusers getting their reasoning from the Bible.

And of course there is the good old Armageddon to look forward when all the faithful adherents will get their reward whilst the non believers will receive their just desserts.