While discussing the hilarious commotion over the Anglican priest who gave a dog a communion wafer, the otherwise sensible Edward Michael George conflates Roman Catholic doctrine with that of Christianity at large:
Telling reporting as always … You see, the thing about giving the body of Christ to a dog is not so much that it offends any particular ‘rule’ or ‘regulation’ of the Anglican Church, as that it rather conspicuously offends what Christians believe (have to believe, if they are Christians) is the person of God himself.
— George, Edward Michael. “Take, eat; this is my Scooby Snack, which is given for you.” Semper Poo Poo, 22 July 2010.
The idea that the communion wafer becomes the actual, literal body of Christ is a doctrine known as transubstantiation. The Roman Catholic and Orthodox churches believe it to be true, whereas many Protestant denominations hold that the bread and the wine are merely symbolic of Christ’s body, and do not at any point become the actual article.
Transubstantiation is by no means a doctrine held in common across the whole spectrum of denominations which call themselves Christian. In fact one of the founders of the Anglican church, Thomas Cranmer, specifically wrote against the doctrine of transubstantiation in his landmark 39 Articles of Religion:
Of the Lord’s Supper
Transubstantiation (or the change of the substance of Bread and Wine) in the Supper of the Lord, cannot be proved by Holy Writ; but is repugnant to the plain words of Scripture, overthroweth the nature of a Sacrament, and hath given occasion to many superstitions.
De Coena Domini
Panis et vini transubstantiatio in Eucharistia ex sacris literis probari non potest, sed apertis Scripturae verbis adversatur, sacramenti naturam evertit, et multarum superstitionum dedit occasionem.
— Cranmer, Thomas. “The 39 Articles of Religion“, written circa 1553, approved by the Anglican Church circa 1562.
Whether or not one finds the notion of a dog receiving communion offensive depends largely on what one thinks about transubstantiation—mainly, whether it occurs or not.