Well, yes, clearly. But the original argument makes sense only assuming a unique and stable tradition that has determined the values you were brought up with. If this happens to be the tradition of some realistic Christian church (or Jewish denomination), chances are that the text of the Bible is only one element of this tradition -- it definitely doesn't imply the whole content of the tradition by itself, and it may well even contradict parts of it, or at least be harmonized only with strained interpretations. (All this even if an opposite pretense is maintained.)
To evaluate the argument from the original article accurately, it is necessary to have a realistic picture of what the tradition in question exactly consists of. It is mistaken to assume that the answer to that question is simply the text of the Bible.
I just had a long conversation with my brother, a devout Christian. With my help he has outlined the following argument why it might be good for me to follow Christian deontology:
What do you think?