I would guess that many (most?) Protestants that have thought about the Catholic position regarding the Mass would (incorrectly) understand that position as meaning that Christ is sacrificed again…and again…during the Mass. Naturally, Protestants reject this view point. See for example one passage from the Eucharist service from Rite I of the Episcopal Book of Common Prayer:
“All glory be to thee, Almighty God, our heavenly Father, for
that thou, of thy tender mercy, didst give thine only Son Jesus
Christ to suffer death upon the cross for our redemption; who
made there, by his one oblation of himself once offered, a full,
perfect, and sufficient sacrifice, oblation, and satisfaction, for
the sins of the whole world; and did institute, and in his holy
Gospel command us to continue, a perpetual memory of that
his precious death and sacrifice, until his coming again.”
(Emphasis added)
Now, it could be that Catholics could even accept the language set forth above because Christ WAS offered only once for our redemption. Still, while I might be wrong on this, I suspect that the language used in the BCP is there at least in part to respond to the Catholic position.
It was only after readings some posts and references in these forums that I learned some of the nuances of the Catholic understanding of the Mass as being a re-presentation of Calvary. FWIW, the “time warp” explanation, although probably irreverent, helped me to at least grasp the concept.
BTW, to show the ambiguity often found in the BCP (including ambiguity that supports a Catholic understanding of the Eucharist), see the response below. Note the present tense of the word “is” as opposed to using the word “was”.
“[Alleluia.] Christ our Passover is sacrificed for us;
Therefore let us keep the feast. [Alleluia.]”
[Emphasis added]