Not sure what your point is supposed to be here. I've been aware for two decades that that ending was tacked onto Mark, and that the historical-critical method undermines Christian inerrantism and fundamentalism.

How is that an objection to my article's point that liberal Christianity reduces to secular humanism? You're simply providing one of the reasons for that reduction, which is that the objective study of the New Testament undermines naive faith in Christian theism.

If I had to guess, I'd say your point is supposed to be that liberal Christians somehow distinguish themselves from secular humanists while accepting the results of the historical-critical approach to the Bible and to the origins of Christianity. But that's the question at issue here, and just pointing to a fact that undermines a more naive form of Christianity hardly helps your case.

If the Bible has been so edited as a human product, why think it's revelatory at all, or more revelatory than lots of other great works of literature? Why trust in the Bible's miracle stories but not in those that are central to other religions' scriptures? Why make an exception of the New Testament, and thus why should the liberal Christian be more committed to Christianity than, say, to Islam or to Hinduism, if she thinks that all scriptures are ancient, highly edited, human products?

My article's not saying that all Christians should be naive literalists who need to accept the Great Commission passage. I'm just pointing to the dilemma that Christians face, between fundamentalism and the reduction to secular humanism (via rational liberal scholarship). If the liberal Christian rejects the Great Commission passage, why doesn't he or she reject also the Passion narrative? Why accept anything supernatural in the gospels as historical fact, on liberal grounds?