We often feel that a clever aphorism captures a truth that would require pages to defend in any other way.
Of course, genes can't pull the levers of our behavior directly. But they affect the wiring and workings of the brain, and the brain is the seat of our drives, temperaments and patterns of thought.
There's no reason that we should give up that lever on people's behavior - namely, the inhibition systems of the brain - just because we're coming to understand more about the temptation systems.