The MC is not a GM that is specific to Apocalypse World, but rather is a more universal type of GM who?s player-centric focus would be at home in nearly any game system and in front of any group. The MC is a great model for an improv GM. With it?s focus on player actions, and with a list of Principles and Moves, it provides the improv GM with a framework to play within.
Do you mean that they supplied Poison'd PDFs online, or their own PDFs? If Poison'd PDFs, can you email me a link?
Unless they're giving away my actual work, there's nothing on that site I can object to. They're using maybe a couple of ideas from one of my games, but pff, all ideas are always free. It's work that has value.