Better not spread that usage around or we’ll soon have ‘End Stage Christianity’ and we all know where that is supposed to … ummm … end (even if it does end a little rapturously).
Edited to add that actually, you were right first time. It IS Late Stage Christianity - they believe it really IS near/just before the end and that’s the main reason that NOTHING FUCKING MATTERS ANY MORE, DOES IT?!?!?
I wish they’d all just hurry up and die and fuck off to their perfect heaven and leave the rest of us sane people to try and figure things out properly for ourselves.