1. Mohler’s books is not an offensive move, it’s a response to the unreasoned attacks by such as Dawkins, Hitchens, etc.

2. Even secular sources correctly define apologetics as defensive in nature.

3. As far as defending atheism, there’s a certain absurdity in the idea of mounting a heavy defense of nothing, is there not? “This doesn’t exist, and I will defend its non-existence with all my strength!”

4. Mohler’s book is, obviously, not attacking reason, but atheism. Suggesting that it is attacking reason is a strawman at best. Contrary to many atheists’ propaganda, faith and reason can coexist and Christianity is quite reasonable. Start here. Then move on to 2,000 years of theology by some of the brightest minds in history.

You have hit the nail on the head as far as motivation, though… The atheist’s position serves them well.

“We will let them come Lt. Let them dash themselves against our bulwarks. The fort of reason has served us well- Isee no reason why this newest fanfare will do any more than buckle and die when it hits our line.”