Then it's useless killing because without the shedding of blood, there is no forgiveness of sins.
And if it's a bloodless sacrifice, then it's not one and the same as the sacrifice of Calvary because that was a bloody sacrifice.
And if the sacrifice of the mass is a bloodless one, then where does the blood that Catholics claim they drink come from?
They pretend it doesn't physically change, but magically, inside, apart from actual molecules, they were taught it is something else.
Made up out of invisible whole cloth.