There are two listed on YouTube, plus the Bertrand Russell essay as well as a dozen others, such as this one: http://www.infidels.org/library/modern/richard_carrier/whynotchristian.html . Without a link it is hard to know which one you refer to. Most atheists love to refer to either books or philosophers, just as Christians use the Bible. . The problem with most of these denial statements is, "So what? You aren't a democrat or republican or whatever, and somehow this means I shouldn't be? How is this convincing, no matter what your views?" Logically, in the Bible, God's call is without repentance, so if you did repent, it's likely wasn't God's call. To say you aren't a Christian, says that God is able to be frustrated. It must be quite fun to be able to show God as powerless! But on the contrary, He allows you the gift of deciding for yourself, for love that is commanded is not love. If you decided you do not love him, nobody can say your decision is wrong; neither is it a priori correct for another. Notice, these people do not say, "why I am no longer saved," they say "Christian," because its ostensibly easier to identify one than the other. But I submit it is possible they were not saved in the first place, merely raised as a nominal theist. If they insist they were saved, then one must ask, "Why would you jump from a lifeboat into the ocean?". The answer to this typically is that they fear the judgment of their life, so must deny the judgment or the Judge. This is Bretrand Russel's ultimate reason: he denies hell, as well as judgment. Curiously, he is like a man who leaps from a 10 story building, denying the fact of a rapidly approaching sidewalk.