There is always someone who says things like this. It's funny how the claims of the detractors also contradict each other, whereas the Scripture continues to stand the test of time.
Also, if the Apostles, who were also busy doing things like preaching, and being bishops,
had some secretary or other helpers to write things down for them, so what? If a person has an assistant, that makes him a forger?
Then again, Ehrman can't support the Gospel, because if he did, he'd have to stop cranking out his factory of facile 'this isn't really what it says' books, which cater to the confused.