How serious is the sin of scandal when committed by a priest?

In recent posts I have examined Father James Scahill's blasphemous assertion that the Holy Catholic Church is "insidiously evil." Just how serious is the sin of scandal when committed by a priest? St. Alphonsus De Liguori, a Doctor of the Church and a moral theologian, explains that, "The Lord ordained in Leviticus that for the sin of a single priest a calf should be offered, as well as for the sins of the entire people. From this Innocent III concludes that the sin of a priest is as grievous as the sins of the whole people. The reason is, says the Pontiff, that by his sin the priest leads the entire people into sin ('Unde conjicitur quod peccatum Sacerdotis totius multitudinis peccato coaequatur, quia Sacerdos in suo peccato totam fecit delinquere multitudinem' - In Consecr. Pont. s. I.) And, long before, the Lord himself said the same: 'If the priest that is anointed shall sin, he maketh the people to offend.' Hence, St. Augustine, addressing priests, says, 'Do not close heaven: but this you do if you give to others a bad example to lead a wicked life.' Our Lord said one day to St. Bridget, that when sinners see the bad example of the priest, they are encouraged to commit sin, and even begin to glory in the vices of which they were before ashamed. Hence our Lord added that worse maledictions shall fall on the priest than on others, because by his sinful life he brings himself and others to perdition.'...says St. John Chrysostom, the life of the priest is the root from which the people, who are the branches, receive nutriment. St. Ambrose also says that priests are the head from which virtue flows to the members, that is, to seculars. The whole head is sick, says the Prophet Isaias;...from the sole of the foot unto the top of the head there is no soundness therein. St. Isidore explains this passage in the following words: 'This languishing head is the priest that commits sin, and that communicates his sin to the whole body.' St. Leo weeps over this evil, saying, 'How can health be found in the body if the head be not sound?' Who, says St. Bernard, shall seek in a sink the limpid water of the spring? Shall I, adds the saint, seek counsel from the man that knows not how to give counsel to himself? Speaking of the bad example of princes, Plutarch says, that it poisons not a single cup, but the public fountain; and thus, because all draw from the fountain, all are poisoned. This may be said with greater truth of the bad example of priests; hence Eugene III has said that bad Superiors are the principal causes of the sins of inferiors...St. Bernardine of Sienna writes that many, seeing the bad example of the scandalous ecclesiastic, begin even to waver in faith, and thus abandon themselves to vice, despising the sacraments, hell, and heaven." (St. Alphonsus De Liguori, Dignity and Duties of the Priest, pp. 142-144, 149).

Canon 1364 of the Code of Canon Law: "...an apostate from the faith, a heretic or a schismatic incurs automatic (latae sententiae) excommunication and if a cleric, he can also be punished by the penalties mentioned in can. 1336.."