No, sorry. It’s plagiarism. At least, that’s one real problem. When a work is ghostwritten, a person agrees to write in the voice of another and allow his or her work to be used without attribution. Plagiarism is exactly the opposite. It is the use of another’s work without permission or attribution.
The other real problem, however, is that Driscoll is an outspoken cultural critic and teacher of a particular brand of morality that he styles as Christian. (See for example, this article in the New York Times, “Who Would Jesus Smack Down?“.) This is why people are so angry. He points fingers. He acts as God’s ethical spokesperson, and the image of God he represents is particularly rigid. His rhetoric sounds mean-spirited at times. Many faithful Christians find Driscoll’s ideas, especially around gender roles, deeply troubling. This persona creates a large target in public discourse.
It’s one thing to teach Christian morality. It’s another to speak and act with such little charity. The furor around Driscoll’s “citation errors” may be a tempest in a teapot, but it is a tempest born of the unkindness of his rhetoric.