Oh, wait a second... I see those are *pages*, not *posts*... that must be why... um, duh!! :-)
Yesss! That's the reason.
Posts are text messages that can be replied to - mostly transient.
Pages are static files (e.g. html).
In the first version of Midnight, there was only a single type (entry). However I think they serve different purposes, so I'm curious to see what it can be like.