In order to understand the fallacy of blaming the Second Vatican Council for the current ills affecting the Catholic Church (that is, to understand why doing so is wrong), it is important to understand what the Second Vatican Council actually was.
The Second Ecumenical Council of the Vatican — also known as the “Second Vatican Council” and “Vatican II” and officially known as “Sacrosanctum Oecumenicum Concilium Vaticanum Secundum” — was convoked by Blessed Pope John XXIII to deal with the many challenges facing the Church in the modern age. Thousands of bishops (including those elevated to the position of Cardinal) attended, and many issues were discussed; a number of future popes attended (namely: John Paul I, Servant of God John Paul II, and Benedict XVI). Pope Paul VI closed the Council (Blessed Pope John XXIII had died before the Council came to a close). The Council produced a number of documents, which were issued by the Council after being voted on by those who participated in the discussions pertaining to the issue the document addressed. These documents were to be guides for reforms in and future polices of the Vatican. As such, they did not of themselves institute any reforms or establish any official policy.
Let us take the Mass as an example. The Council issued the dogmatic constitution Sacrosanctum Concilium on the liturgy. Pope Paul VI established a commission to draw up reforms and policies to implement the dogmatic constitution. As the commission produced policies, Pope Paul VI had them instituted. Then Pope Paul VI issued a new missal as the commission came to an end, replacing the individual reforms with one sweeping reform to incorporate and implement the commission’s reforms in order to make effective the Council’s dogmatic constitution thereof. In other words, the Council did not change the Mass: Pope Paul VI (himself and through a commission he appointed) did, albeit based on the statements and recommendations of the Council through its documents.
Now, a separate but important issue needs to be brought up. In the reforms and new policies, many novel ideas and practices were permitted. The idea was to add some novelty and to make things more people-friendly, so to speak. The intent was that on certain occasions and in limited circumstances, priests will take advantage of such measures to provide something different, all the while cleaving to the way things have been done. As such, a lot was permitted and suggested – but only few of these novelties were mandated. In many cases, in order to take advantage of a novelty (such as offering the Mass in the vernacular) a priest would need to have the approval of the local episcopal council, whose decisions in turn would need to be approved by the Vatican. But local episcopal councils and the Vatican were all too eager to approve and promote novelties, which was not foreseen by those who drew up the new rules and regulations. What was supposed to be extraordinary became normative and what was supposed to be normative became extraordinary. People took things too far too fast. Of course, the Vatican — specifically, the leniency of the pope and, subsequently, of his curia — shares part of the blame for what happened: the Vatican could have imposed more discipline and granted fewer approvals for implementing novelties.
But that is the past. With his motu proprio, Pope Benedict XVI did something unprecedented: he essentially approved the use of an older order of liturgy. With his promulgation of a new missal, Pope Paul VI essentially banned all old liturgical orders, which remained the state of affairs under popes after him (with the exceptions provided by Servant of God Pope John Paul II in Ecclesia Dei). Nevertheless, Pope Benedict XVI made it clear that the liturgical order of Blessed Pope John XXIII (the only older order of liturgy approved) was extraordinary and should in no way be seen as a replacement of the ordinary or normative order, which is to remain that of Pope Paul VI with what reforms made by Servant of God Pope John Paul II.