I would counter that the exact opposite is true. Leaning from the ankles is crystal clear. It means exactly what it means: when standing still, you are actually physically bending in the ankles. I will clarify, when you are actually walking, a whole lot of other things are going on. But at the point of the transfer of axis, or at rest with no movement, you are leaning from the ankle.
Leaning from the torso on the other hand is physically impossible, and I assume is just a metaphor and a way to encourage someone to push forward with their entire body.