The thing of it is that I don’t think Ehrman and Wallace really disagree that much about text criticism. For me, the question of whether the text of the New Testament is reliable boils down to the question “Reliable for what?”
My point is that reliability is not a fixed concept; it varies with the application. Sometimes, lack of information is enough to render a thing unreliable. If an airplane has not been through the standard pre-flight safety check, it’s not reliable. Even if it’s in perfect working order and capable of passing the check with flying colors, no pilot should take it up and no passenger should board it. On the other end of the spectrum might be my fifteen-year-old lawn mower. If I can get it started by the tenth try and it doesn’t die more than a half dozen times while I am cutting the grass, it meets my criteria for reliability. The same electric motor that might be perfectly reliable in a vacuum cleaner might not be reliable in a respirator.
That’s why I am not persuaded by people who compare the textual reliability of the New Testament to something like the Iliad. After all, what am I going to use the Iliad for other than having an enjoyable read and getting some insight into an ancient culture? There could be an awful lot of variants in there and I would still consider it perfectly reliable for those purposes.
The New Testament, on the other hand, is used for so much more and my question is whether it is reliable for the purposes that it is used. For instance, suppose that Paul wrote something sympathetic about homosexuals in his letter to the Galatians. If we had that verse, we might look at the other verses in his letters that touch on the subject as being directed only against specific groups at specific times and we might look at the Old Testament passages on the subject as anachronisms on a par with the bans on eating shellfish. However, suppose that some scribe in those first 150 years looked at it and said, “This can’t be right,” and deleted it.
Is the text of the New Testament reliable for purposes of deciding social policy towards homosexuals? Is it reliable enough to ban homosexuals from military service? Is it reliable enough to saddle people with a lifetime of guilt over a trait that they cannot control? Is it reliable enough to send a young person into a coercive and potentially destructive course of therapy in order to repress his or her natural desires? I would certainly never think that the Iliad was that reliable.
In my opinion, the problem is that the New Testament text is not sufficiently reliable for the purposes to which it is put.