Aerospace eng. here, you are right in that is a confusing terminology. Ram pressurein this context is a way to refer to the available kinetic energy due to airflow: 1/2 x density x speed^2 (also called dynamic pressure).

A point to stress is that the energy delivered to the plane systems by this auxiliary turbine is thus varying with the square of the speed of the plane. That means that as you slow down for landing, the RAT delivers less and less energy... and the commanding authority of the hydraulic-actuated control surface lowers, making the plane less and less controllable. Not fun!