I read somewhere on this site earlier today that someone asked another why they kept saying "A REAL Christian". I don't remember who - pain med day!!! LOL ;-)
*** DISCLAIMER *** I don't want to put words in anybody's mouth, but let me attempt to explain. This is not the academic piece I would like to launch, but off the top of my head - my Vicodin fogged head. LOL
Constantine, the first Roman Emperor, declared the entire world "Christian" and issued the Edict of Milan in 313, which proclaimed tolerance of all religions throughout the empire. I have read that he even had all his soldiers baptized as Christians but he insisted they raise their right hand out of the water so they could still go into battle (presumably with sword or spear in right hand) and kill but not desecrate their baptism.
Also, with Martin Luther and the protestant movement away from the church, there was a split in the Christian church.
Today public polls have shown that people who do not consider themselves pagan or belonging to an eastern religion will proclaim themselves as "Christian".
So, the term "real Christian" usually stems from the distinction between those who call themselves Christian as a way to denote not pagan and those who follow the Christian religious/belief way of life. Some even use the term “real Christian” to distinguish themselves from those who claim to be Christian but do not follow certain dogma or doctrine; a sort of sibling rivalry within the church. Kind of like the one-upsmanship you might hear within a group of type A personalities (Police, Firefighters, EMTs, military, etc.). The friendly, family-like, banter of “I’m better than you”.
I hope this makes sense. I will probably come back and read this later and scratch my head wondering what was trying to say.
Food for thought.