Cafeterian is a slang term (coined by interweb's Pile) that refers to a theist who claims to be part of a particular religious affiliation (such as a "Christian"), who picks and chooses select aspects of scripture and dogma to follow, while ignoring contradictory or other scriptures, rules and dogma. They basically select what they want to believe in, not unlike one would visit a cafeteria and select specific plates of food, while ignoring everything else.
Convenient bastid! This Cafeterian has condensed the entire nature and history of Christianity into a simple marketable sentence. It's up to us to trust that this guy somehow has figured the whole of Christianity out. Sure.