You wrote: “or regard those who fail to do so guilty of mortal sin.”
A. I do not make that judgment of culpability. One can observe that a person does objective grave sin without determining culpability.
You wrote: “The only “Church rules” which are
required of Catholics are the five Precepts of the Catholic Church. Would you please tell us how charity is the basis of our requirement to attend Mass or days of obligation? Or how charity is the basis of our requirement to receive Eucharist or attend Confession once a year? Or any other Precept?”
A. Actually those are not the only obligations. I compiled a list of over 20 obligations from the canon law.
You wrote: “That is the idea, but I was looking for (as I have explained many times) for sins of positive precept which concern matters of charitable acts (which benefit others), not subscription to Church rules (which benefit ourselves).”
A. Charitable acts benefit others but also benefit ourselves spiritually. We must follow those rules which are obligatory for more than one reason, one of which is not to give scandal, which is uncharitable. Our compliance also benefit others: we give witness to our faith. We are members of the Church of Christ, a universal Christian community.
I posted before on scandal. This is from Baltimore Catechism:
Q. 1277. What is forbidden by the fifth Commandment?
A. The fifth Commandment forbids all willful murder, fighting, anger, hatred, revenge, and bad example.
Q. 1278. Can the fifth commandment be broken by giving scandal or bad example and by inducing others to sin?
A. The fifth commandment can be broken by giving scandal or bad example and inducing others to sin, because such acts may destroy the life of the soul by leading it into mortal sin.
Q. 1279. What is scandal?
A. Scandal is any sinful word, deed or omission that disposes others to sin, or lessens their respect for God and holy religion.
This is from the later Catechism of the Catholic Church:
Respect for the souls of others: scandal
**2284 **Scandal is an attitude or behavior which leads another to do evil. the person who gives scandal becomes his neighbor’s tempter. He damages virtue and integrity; he may even draw his brother into spiritual death. Scandal is a grave offense if by deed or omission another is deliberately led into a grave offense.
2285 Scandal takes on a particular gravity by reason of the authority of those who cause it or the weakness of those who are scandalized. It prompted our Lord to utter this curse: "Whoever causes one of these little ones who believe in me to sin, it would be better for him to have a great millstone fastened round his neck and to be drowned in the depth of the sea."85 Scandal is grave when given by those who by nature or office are obliged to teach and educate others. Jesus reproaches the scribes and Pharisees on this account: he likens them to wolves in sheep’s clothing.86
**2286 **Scandal can be provoked by laws or institutions, by fashion or opinion.
Therefore, they are guilty of scandal who establish laws or social structures leading to the decline of morals and the corruption of religious practice, or to "social conditions that, intentionally or not, make Christian conduct and obedience to the Commandments difficult and practically impossible."87 This is also true of business leaders who make rules encouraging fraud, teachers who provoke their children to anger,88 or manipulators of public opinion who turn it away from moral values.
**2287 **Anyone who uses the power at his disposal in such a way that it leads others to do wrong becomes guilty of scandal and responsible for the evil that he has directly or indirectly encouraged. "Temptations to sin are sure to come; but woe to him by whom they come!"89