The unacceptable inference is, of course, that women somehow bear some responsibility for rape. Note the word inference, not implication. Far from it. He recognizes that rape is a male problem, though possibly rooted in biological urges that deserve scrutiny. Rape is violent, yes.
Rape is coercive, yes.
But these facts do not negate the possibility that rape is also, at least sometimes, sexually motivated. The authors peg their theory on an evolutionary tenet, the same one, ironically, that we've accepted as an explanation for male promiscuity - the biological imperative to impregnate as many females as possible. Rape as violence, meanwhile, is a given inasmuch as anything physically coercive is violent. Because Those Who Speak for Women too often refuse to entertain any deviation from the party line. If you accept that rape is a sexual act, then you must also accept that certain social behaviors may trigger the rapist.