The Catholic Mass certainly calls the Passion a sacrifice. Is your objection to the word or to the word's essence?
To the Protestant notion that it was demanded, i.e. a necessity (based on distorited juridical concept of an "offended" God, prevelant in the West, that could, by necssity, be satisfied only by a sacrifice of equal dignity! So God kills God in order to be "satified.")
God is not subject to necessity.
Christ did offer Himself by His own will, which is also the will of the Father, obviously. But that sacrifice was voluntary, an act of love, a gift, not a necessity.