Who is a Christian?

As my criticism of Christianity often focuses on the belief in a place of eternal punishment for nonbelievers and other sinners, sometimes I receive the response that not all Christians believe in hell. Since they cannot deny that in the gospels Jesus frequently spoke of hell and threatened his listeners with damnation for failure to follow him, they offer various explanations of these texts: he never said anyone will actually be damned, he was speaking metaphorically, he just meant you have to be a good person, he just meant you have to believe in something, he didn't really say this, he never really existed or even God doesn't exist! (Most often, however, they offer no explanation whatsoever and simply ignore the question completely, giving it no thought at all.) We find each of these views held by self-identified Christians, but how can one label apply to people with such disparate opinions and still retain any useful meaning? I'm well aware of the danger of falling into the No True Scotsman fallacy, but it seems we need to draw the line somewhere. There are perhaps as many different Christianities as there Christians in the world, but as for me, whenever I present criticism of the religion in this blog, I implicitly refer to the basic theology shared by Catholicism, Eastern Orthodoxy and Protestantism unless otherwise stated. I'm arguing against a specific collection and system of beliefs, not the label “Christian,” which can be and has been applied indiscriminately to almost anything. If I criticize a belief which you yourself don't hold, then you can ignore it and move on.