Christians did not attain that number by including or excluding anyone. The number is arrived at by simply counting those calling themselves "christian".<quoted text>And therein lies the difficulty.
Christianity claims a membership of about 2 billion - but in order to attain that number, they have to include groups that they'd otherwise cheerfully consign to the flames.
Catholics, Mormons, JWs, Christian Scientists, snake-wigglers, Westboro Baptists...
You are a blithering idiot.