[quote="internetjoko, post:1, topic:333424"]
If the Church has the power to reduce temporal punishment, apparently allocating the 'stored up' merits of the saints and loosing them as they see fit on people who participate in certain acts of faith & charity, etc... Then doesn't this render purgatory unnecessary? This is, essentially, why protestants see no need for purgatory & why, at least theoretically, purgatory is not necessary.
Christ will not use His merits to just remove all of our temporal punishments regardless of what we do or not do, for that would be to infringe Divine Justice. It is written:
Leave there your gift before the altar, and go your way; first be reconciled to your brother, and then come and offer your gift. Agree with your adversary quickly, whiles you are in the way with him; lest at any time the adversary deliver you to the judge, and the judge deliver you to the officer, and you be cast into prison. Truly I say to you, You shall by no means come out there, till you have paid the uttermost penny.
"Protestants" - a very, veery broad term - may see Purgatory as unnecessary according to their logic, but Purgatory is present in Sacred Scripture and in the teachings of the Church Fathers. Please, kindly check these two posts I link, since it took me a fair amount of time to collect those details.
Now we do not like to claim to know better than Protestants...but it does seem they do claim to know better than the Church Fathers, and on that we must respectfully disagree.
About Twitter (the red herring in your title, I mean), another user reminded us
All indulgences require confession, communion and a prayer for the intentions of the Pope in addition to a particular pious act. The Pope has now added a new "pious act" to the list and it happens to be in keeping with the digital age.
Catholic Encyclopedia teaches us about indulgences (emphasis mine).
What an indulgence is not
It is not a permission to commit sin, nor a pardon of future sin; neither could be granted by any power. It is not the forgiveness of the guilt of sin; it supposes that the sin has already been forgiven. It is not an exemption from any law or duty, and much less from the obligation consequent on certain kinds of sin, e.g., restitution; on the contrary, it means a more complete payment of the debt which the sinner owes to God. It does not confer immunity from temptation or remove the possibility of subsequent lapses into sin. Least of all is an indulgence the purchase of a pardon which secures the buyer's salvation or releases the soul of another from Purgatory. The absurdity of such notions must be obvious to any one who forms a correct idea of what the Catholic Church really teaches on this subject.
What an indulgence is
An indulgence is the extra-sacramental remission of the temporal punishment due, in God's justice, to sin that has been forgiven, which remission is granted by the Church in the exercise of the power of the keys, through the application of the superabundant merits of Christ and of the saints, and for some just and reasonable motive.
In the Sacrament of Baptism not only is the guilt of sin remitted, but also all the penalties attached to sin. In the Sacrament of Penance the guilt of sin is removed, and with it the eternal punishment due to mortal sin; but there still remains the temporal punishment required by Divine justice, and this requirement must be fulfilled either in the present life or in the world to come, i.e., in Purgatory. An indulgence offers the penitent sinner the means of discharging this debt during his life on earth.
The satisfaction, usually called the "penance", imposed by the confessor when he gives absolution is an integral part of the Sacrament of Penance; an indulgence is extra-sacramental; it presupposes the effects obtained by confession, contrition, and sacramental satisfaction. It differs also from the penitential works undertaken of his own accord by the repentant sinner — prayer, fasting, alms-giving — in that these are personal and get their value from the merit of him who performs them, whereas an indulgence places at the penitent's disposal the merits of Christ and of the saints, which form the "Treasury" of the Church.
An indulgence is valid both in the tribunal of the Church and in the tribunal of God. This means that it not only releases the penitent from his indebtedness to the Church or from the obligation of performing canonical penance, but also from the temporal punishment which he has incurred in the sight of God and which, without the indulgence, he would have to undergo in order to satisfy Divine justice. As St. Thomas says (Supplement.25.1 ad 2um), "He who gains indulgences is not thereby released outright from what he owes as penalty, but is provided with the means of paying it."
In granting an indulgence, the grantor (pope or bishop) does not offer his personal merits in lieu of what God demands from the sinner. He acts in his official capacity as having jurisdiction in the Church, from whose spiritual treasury he draws the means wherewith payment is to be made. The Church herself is not the absolute owner, but simply the administratrix, of the superabundant merits which that treasury contains. In applying them, she keeps in view both the design of God's mercy and the demands of God's justice. She therefore determines the amount of each concession, as well as the conditions which the penitent must fulfill if he would gain the indulgence.