So that jesus can torture the bad persons.

For sharing between users, as I understand it.

So they know what sins I’ve committed.

They don’t follow my mastodon feed. It’s much easier that way.

Historically? Abuse.

I’m sure they say it’s for security : blocking bots, etc and getting their newsletter or some shit.

They need the list of who's been naughty and who's been nice.

Or is that the other fella?

I expect they're using some kind of authentication framework that supports full names in its User entity, and just went with that without considering whether it's sensible.

Looks like you can leave comments on prayers? Could also be that they want a particular aesthetic where everyone has their innate "Christian Name", instead of a username, which is assocated with left wing ideas like digital utopianism. Because...

Real names also enforce a complex of related authoritarian information structures i.e. they provide information about a person's culture, race, gender, which you can use to assign them a place within your religion's moral hierarchy.