Would the real christian please stand up? - May 19,2014

Every time I talk to a believer these days, I hear two things: the believer thinks most christians are wrong and those christans are not following the bible; and the believer to whom I am speaking is right and IS following the bible. What's us with the no-true Scotsman nonsense? Why is this used so damned often? How can atheists respond to it? My thoughts plus your calls equal awesomeness.