Gibberish. Just because it is hard does not mean it is not a choice.
The problem that religious institutions face in the US today is that they have essentially ignorant morons for leaders. They may know ancient Greek and study Origen and Iraneaus but they don't know jack squat about the real world. They have a psych 101 level understanding of human behavior and act like they are scholars. They are not. Mohler's statement here is a picture of unethical incompetence, and he does not even know how ignorant he is. Because he is "ordained" by god, I guess, to make a consummate ass of himself.
The troubling part is, the whole mainline is even worse off. The episkie church is teaching that "abortion is a blessing and our work is not done." Imagine what they think about homosexuals--oh, come to think of it, the president of the piskie divinity school is a homosexual. Makes Mohler look tame by comparison, but he's not.
I think you are misunderstanding Mohler’s point. He is not saying that it isn’t a choice, he is saying that it is more than just a choice. It takes the power of God to turn something like homosexuality around, not the mere choice of men. He isn’t saying that it isn’t a choice whatsoever. Basically, he thinks Evangelicals have portrayed it as something you can just turn on and off, and that is simply not true.
You have to remember that Mohler is an outspoken Calvinist. He has a much higher view of the power of sin than the average Evangelical, as do I. That is probably what lies at the root of these comments here.