David is simply embracing the well-documented first-century mocking pagan slander that Christians were "cannibals" and therefore "haters" of the human race, and those charges justified Nero's mass torture murders of Christians in the pagan Roman mind. As a Pentecostal Methodist, I myself don't believe in the underlying Thomistic Aristotelian metaphysics of the Catholic doctrine of Transubstantiation. But I much prefer the spirituality of this Catholic doctrine to the dumbed down Baptist doctrine of a merely symbolic Holy Communion. My first church upset me with their longstanding practice of celebrating Holy Communion only 4 times a year. I insisted that they have Communion at least once a month, and they grumbled that Communion would then be a dull, empty, and merely symbolic ritual. The high Catholic reverence for the sacraments illustrates their desire to be viscerally engaged with the truth of Christ's atoning sacrifice each week. It is that special reverence that has draw Evangelicals from their churches in my town to the local Catholic church, where, at last, they find the crucified and risen Christ real in the Eucharist.
Most evangelicals fail to grasp the need to experience an intimate connection with Christ through Eucharistic participation. They don't realize that the right expectation from this holy act renews their ability to "abide in me, and I in them (John 6:55-56):"
"My flesh is real food and my blood is real drink. Those who eat my flesh and drink my blood abide in me, and I in them."
An evangelical attitude that trivializes Communion as a merely symbolic act leaves them open to participating in Communion in "an unworthy manner" that disrespects the Lord's presence in this sacramental act:
"Whoever eats the bread and drinks the cup in an unworthy manner will be answerable for the body and blood of the Lord!...For all who eat and drink without discerning the body at and drink judgment against themselves. For this reason, many of you are weak and ill, and some have died (1 Corinthians 11:27, 29-30)."
The divine judgment for a cavalier attitude towards the Eucharist can be severe because the participants are not discerning body of the crucified Christ through their harmonious discernment of the earthly manifestation of Christ's body, the church.