The whole business of the Mass being an unbloody or bloody sacrifice is the problem.
The Mass is the renewal and perpetuation of the sacrifice of the Cross in the sense that it offers anew to God the Victim of Calvary and thus commemorates the sacrifice of the Cross, reenacts it symbolically and mystically,... (uh oh...ellipsis alert!)
11Every priest stands daily ministering and offering time after time the same sacrifices, which can never take away sins; 12but He, having offered one sacrifice for sins for all time, SAT DOWN AT THE RIGHT HAND OF GOD, 13waiting from that time onward UNTIL HIS ENEMIES BE MADE A FOOTSTOOL FOR HIS FEET. 14For by one offering He has perfected for all time those who are sanctified. Hebrews 10:11-14
There is no need of any sacrifice. Period.
It's already been done.
As He said on the Cross: Τετέλεσται