"First, Catholics do not receive our Lord in a cannibalistic form. Catholics receive him in the form of bread and wine. The cannibal kills his victim; Jesus does not die when he is consumed in Communion. Indeed, he is not changed in the slightest; the communicant is the only person who is changed. The cannibal eats part of his victim, whereas in Communion the entire Christ is consumed—body, blood, soul, and divinity. The cannibal sheds the blood of his victim; in Communion our Lord gives himself to us in a non-bloody way."
The Roman Catholic Eucharist does indeed imply cannibalism, since it includes literally consuming the human flesh of Jesus Christ. Eating only part of a victim does not remedy this dilemma. A cannibal does not cease to qualify fitting under that label just because he has eaten a whole victim or does so in a different manner.
"Second, if it were truly immoral in any sense for Christ to give us his flesh and blood to eat, it would be contrary to his holiness to command anyone to eat his body and blood—even symbolically. Symbolically performing an immoral act would be of its nature immoral."
The usage of symbolism does not suggest as a logical consequence a literal understanding or act practiced. Jesus Christ is our source of spiritual sustenance. We partake of Him by trusting in His work on a continual basis. He is not life to us because we literally eat His flesh and drink His blood.
How come the inspired writers of the New Testament never clarified that the eucharist was not cannibalism?
"Moreover, the expressions to eat flesh and to drink blood already carried symbolic meaning both in the Hebrew Old Testament and in the Greek New Testament, which was heavily influenced by Hebrew. In Psalm 27:1-2, Isaiah 9:18-20, Isaiah 49:26, Micah 3:3, and Revelation 17:6-16, we find these words (eating flesh and drinking blood) understood as symbolic for persecuting or assaulting someone. Jesus’ Jewish audience would never have thought he was saying, “Unless you persecute and assault me, you shall not have life in you.” Jesus never encouraged sin. This may well be another reason why the Jews took Christ at his word."
Just because a figurative expression has a negative connotation in certain contexts, it does not follow such always has that same meaning or intention. That would be an exegetical fallacy. Interpreting the teaching of Christ during the Bread of Life Discourse as being a reference to transubstantiation misses the entire point of the passage. See this article for more details:
Transubstantiation conflicts with the nature of the miracles that take place throughout Scripture. Two examples would include the marriage at Cana (John 2:1-10) and the doubting Thomas touching the resurrected Christ's pierced hands and feet (John 20:26-29). Unlike the eucharist, scriptural miracles were recognizable to the five senses.
If transubstantiation is true, then the consecrated elements should taste like human flesh and blood. But that is obviously not the case. The communion elements taste like bread and wine even after consecration by the priest. The literalist interpretation of the Lord's Supper is absurd beyond all measure. There is something wrong with a proposition which tells us that things are not consistent to the reality of our surroundings.
If transubstantiation is true, then that would mean the full human body of Christ is literally inside the stomachs of partakers during the liturgical service. Even getting His entire body into our mouths at one time would be an impossibility. These conclusions are nonsense, as our digestive system would obviously be holding far beyond its natural capacity.
Jesus Christ has a material body, just as we all do. That means His body and blood would have been consumed a long time ago. His body and blood would have been all eaten up. His body and blood would have been gone two thousand years ago, thereby making transubstantiation in future generations a logical impossibility! Nothing is sacrificed during the Mass except one's own common sense.