mugshots use of XMPP (or Jabber)

I browsed a little further thru the mugshot developer”s wiki and found the discription of their use of XMPP. They seem to abuse multi user chat rooms to emulate a publish-subscribe model. What was the architectural decision to do so and not to use XEP-0060? I wonder if that behavior is the reason for the patches they applies to Wildfire?!