Hi,
Actually, not all Catholics are allowed to receive Holy Communion either. They need to have been instructed on what the Church teaches about the Eucharist and ACCEPT such teaching. They also must be in the state of grace. If they have a mortal sin on their souls, they must receive absolution from a Catholic priest first. In having such requirements, the Church is not punishing anybody or putting them down—and here is where 1 Cor. 11:28b comes in: “a person who eats and drinks without recognizing the Body is eating and drinking his own condemnation.”
Above all, the Eucharist is the greatest sign of unity that we have. Unfortunately, Catholics and Protestants are not united in what they believe about the Eucharist. (Lutherans believe in “consubstantiation” where the bread and wine remain bread and wine and somehow the presence of Christ is next to the bread and wine.) To jointly receive it would make the Eucharist a sign of a unity that doesn’t exist at this time. Such a lie would be a sacrilege.
Fr. Vincent Serpa, O.P.