Their full name is the "Church of Man." They are an anti-technology group that shows up in Priv/RF. They play a large part in RF's story as well.
Close but wrong. The Retros are a renegade cult that started as part of the Church of Man but spilt off because they wanted to force all of humanity to live by the Church of Man's beliefs concerning technology.
Thanks to all who replied; so are these 'Church of Man' renegades terrorist or pirate organization or would they be considered to be "Kat Sympathizers/collaborators"?
But seriously, 'Retro' is the slang term for the group... they (meaning the group of radical terrorists) are called the Church of Man almost everywhere (including in the manual, in all the Righteous Fire dialogue, in the official guide, etc.) I'm not sure how the mistake could be made in the first place, much less insisted upon.
It's been years since I read the guide but I could swear that it referred to them as an off-shoot of the Church of Man.