Well, that was a role he was playing.

I think they are consistent with the angels (until 8x02), but hey, who knows, maybe they are consistent with the demons too, and we just don't know. Maybe Alistair wasn't actually Alistair and Lilith wasn't actually Lilith.

So, it could actually be a rule that demons either chose a pseudonym to work under or simply don't care what you call them.