Does anyone have a good resource about when Communion can legitimately be denied?
From SSPXMust a priest follow certain criteria if he is to refuse Holy Communion to the faithful?A priest does not have the right to refuse Holy Communion arbitrarily. He must follow the requirements of Canon Law, which prescribes to whom he must refuse Holy Communion, and to whom he must administer it. This law is to be found in Canon 855, §1:
Catholics who are publicly known to be unworthy (for example, those who have been excommunicated or interdicted or who are manifestly of ill repute) must be refused Holy Communion until their repentance and amendment have been established, and satisfaction has been made for the public scandal which they have given.
The essential part of this law is that a Catholic must be a public sinner, or publicly unworthy, to be refused the sacrament of Holy Communion. This is the case, for example, of a person who has publicly performed abortions, or voted for legislation in favor of abortion; or of a father who would have had his children baptized and raised in an heretical sect; or giving membership to the Communist party, or public concubinage; or of persons divorced and remarried outside the Church or convicted of civil crimes such as pedophilia.
However, the Church is very clear that Holy Communion cannot be refused to a person who is not a public sinner, that is if his sin is not sufficiently well known in the community at the present time. For to refuse Holy Communion to a person who is not known to many people as one who publicly breaks the commandments of God would be to defame his good name and destroy his reputation, which a person has a right to in justice, even if he is a hidden sinner. It is only by public sin that he loses this right, for he has lost his reputation. However, if such a hidden sinner were to ask the priest in private to receive Holy Communion, or whether or not he can go to Holy Communion, the priest would be obliged to forbid him to go to Holy Communion, and this even though he could not refuse him Holy Communion if he were to request it publicly at the communion rail. This is explained in the second half of Canon 855: “Occult sinners, who secretly ask for Holy Communion, shall be refused by the minister if he knows that they have not amended; if, however, they seek Communion publicly and the priest cannot pass them by without scandal, he shall not refuse them.” It is truly sad for a priest to be obliged to administer a sacrilegious Communion, but if he cannot convince them privately to abstain from going to Holy Communion, then he must do so.
The question can sometimes arise, not of hidden or occult sins, but of public attitudes that persons might take against the Church, but which are not public sins. There are some people who lack respect for their priests, refuse to follow their advice and counsel, who cause dissension in a parish by gossip and similar means. In general, they are not to be considered as public sinners or publicly unworthy, unless they openly promote teachings that are opposed to Catholic Faith and morality, or unless they incite other parishioners to direct disobedience and disrespect towards their pastors. On occasion, sedevacantists and Feeneyites have fallen into this category.
Also, when parents obstinately refuse their very grave duty of educating their children in the Catholic Faith, as required by canon 1113, and instead educate them in a non-Catholic religion, they must be refused Holy Communion. Canon 2319 (1917 Code of Canon Law) stated that they are to be treated as excommunicated, and consequently refused the sacraments.