We absolutely must practice mercy and forgiveness, but not at the expense of justice and security. St Augustine's doctrine of just war does not contradict Christ's admonition to "turn the other cheek".
Isn't catholic social doctrine dictated by the pope?
In other words, the pope trying to dictate social doctrine would result in massive unpopularity or schism. That is why this pope is unpopular in some circles. Whether that's deserved or not is not an argument I'm having today.
To be precise, social doctrine that is contradictory to what the Church previously taught would be a problem.
The Pope can and should and does dictate correct Catholic social doctrine.
Yes, but it's more akin to how US Foreign Policy is dictated by the President.
Ignoring the religious aspect for a bit. The Pope has the power to dictate Catholic social doctrine, but he primarily interprets existing doctrine, which has been established over 2000 years. I don't believe that the current Pope has taken any steps to explicitly change doctrine, merely to explain it.
For example, the church considers abortions to be a sin (murder). This has often resulted in penalties and bias against women who have had an abortion within the church. Pope Francis has called for more love and respect towards these women. This was not presented as a change in doctrine, however the language is imprecise so it can be interpreted as "abortion is not a grave sin" or as "love the sinner, hate the sin." Obviously people will use the imprecision to support their agenda.
For instance, the Bible does mention how to deal with issues of bioethics, modern financial and economic systems, and many other topics because they simply didn't exist at the time.
So we need Church authorities to apply and interpret these teachings to modern issues. The Pope can and should and does tell us how to apply Catholic teaching in modern situations, but he might communicate poorly (this is a real problem with Pope Francis), or even make mistakes.
Papal infallibility is very specifically and narrowly defined and is rarely applicable. It has only been invoked twice in the last 150 years, both times for doctrinal statements relating to Mariology (i.e., Mary the Mother of God, not the monkey-fighting plumber guy, although I find that idea amusing).
In both cases, Pope Pius IX and Pius XII were establishing as doctrine teachings that had been believed and taught for centuries, and which refined, but did not fundamentally change anything.
Popes sometimes refer to an infallible statement, but this is merely a reiteration of existing doctrine (e.g., When Pope John-Paul II invoked infallibility in the restatement that the Church does not have the authority to ordain women, but he wasn't saying anything new).
The Pope's authority is valid only in as much as he is consistent with the teachings passed down from the Apostles, and when he is making statements that are consistent with Catholic teaching and in communion with the bishops and traditions of the Church.
As an example, Pope Francis' claims that capital punishment is always wrong contradicts traditional Catholic teaching. Now the application of capital punishment in a modern society may be unacceptable for reasons of the protection of rights of the accused (e.g., overturning a wrongful conviction doesn't any good if the no-longer-a-convict is dead), maintaining safety (e.g., life imprisonment keeps society safe from people who are too dangerous to be in society), and the process is just too unwieldy to be exercised in an efficient and just way (e.g., people being on death row for decades through endless appeals).
But this does not mean that capital punishment is inherently wrong, and this is what the Church has always taught. Francis is expressing an opinion here, one that is worth considering, but he is not changing Church teaching because he can't.
For the record, I don't support capital punishment, but for reasons stated above, not because it's inherently wrong, but because it is not necessary. If I were living in a small community on an isolated island, or in many other situations, my opinion might be different.
This is a common but absurd misconception, implying that only twice in 2000 years a pope made a statement that fulfills the requirements outlined in Vatican I, ie. making a statement 1) regarding faith and morals, 2) directed to the entire church.
You will also get a taste for how possible and how surprisingly often individual bishops misrepresent it, both today, and in the past.
Then again the monks who taught me were weird (all monks are in my experience) and my family is generally a fairly liberal form of Irish Catholicism. The monks example of evolution of Catholic theory they used was tolerance towards homosexuality becoming more and more prominent in the Church and how eventually it will be accepted as the church adapts to modern thought or the church will die. It fundamentally exists to serve it's constituants and part of that is adapting to them.
For instance, "No meat on Fridays during Lent" is a rule of discipline and bishops are free to modify this or even eliminate it should they wish. Holy Days of Obligation, aside from every Sunday, are also disciplinary rules, and are sometimes different from diocese to diocese, even within a single country (like the U.S.).
Priestly celibacy is also a discipline rule that could be modified (but almost certainly won't be, IMO). It's only been universal in the Roman Church for about 1000 years or so, and some Rites allow for married priests, which is fine.
But the immorality of murder, abortion, sex outside of marriage, the definition of marriage, etc., etc., as well as teachings regarding the Divinity of Christ, the Real Presence and the Sacraments, are moral and theological doctrines of the Church and not subject to revision, and any Pope or bishop that attempted to claim otherwise would be engaging in material heresy.
Now having said that, discipline with respect to the correct teaching of Catholic doctrine has massively broken down (e.g., the monks you described) in the past half century, but that doesn't make it right, and it will eventually be corrected. At one point the vast majority of the Church was Arian, but that wasn't right either, and was eventually corrected as well.
The Church was established by Christ, and exists to correctly pass down His teachings. It is only serving its members by passing down those teachings, which are not subject to change, and by properly exercising the authority granted to it by Christ. Church Doctrine has never changed, and cannot and will not change. This is why there are over 40,000 Christian denominations which split off from the Catholic Church and from each other by attempting to change doctrine.