The "tu quoque" fallacy (or, as I like to call it, the "you did it too" fallacy) is extremely common in Catholic apologetics. Rather than respond to criticisms against the Catholic Church, they instead resort to pointing out that some Protestant group or individual suffers a similar problem.
Now, we could address the irony of the fact that the Catholic Church constantly appeals to the large number of non-Catholic denominations while simultaneously arguing as if they can all be refuted collectively. Instead, we will correct some major misconceptions within the Catholic mind.
First, let us address the problem with the term "Protestant". The term "Protestant" is ridiculously ambiguous. It basically means nominally Christian, but non-Catholic. Already, this opens the door for the large number of denominations previously alluded to. This is nowhere near as major as Catholics claim (I've seen anywhere between 30-60,000), but it is still enough that the term "Protestant" is an illogically wide brush to paint with.
But it gets even sillier when you realise that, second, Catholicism has a radically different authority structure than "Protestants" do. With the exception of heretical sects, Christians believe in what became known as "Sola Scriptura" (scripture alone) during the Reformation. Sola Scriptura dictates that, to quote Augustine, "among the things that are plainly laid down in Scripture are to be found all matters that concern faith and the manner of life." Or, to quote scripture on the matter, "All Scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness, that the man of God may be complete, thoroughly equipped for every good work." (2 Timothy 3:16-17, emphasis on verse 17). In other words, the central authority in the Christian faith is scripture. Pointing to anything a Protestant does and using it to defend Catholicism is like saying wolves are better shepherds because sheep sometimes run away from their actual shepherds.
By contrast, the Catholic Church firmly rejects Sola Scriptura, claiming that their "sacred traditions", as defined by their "Magisterium", are equal to scripture. Conveniently, they also claim to be the only body capable of providing an authoritative interpretation of the scriptures, so basically, they don't always admit that they think they have more authority than the Bible, but they certainly act like they do. Because of this, any action taken by the Catholic Church reflects on them, simply because it is on this same authority that they now take different approaches.
By contrast, although it can be said that Christians owe a great debt to the Reformers, and that, in theory, we should have a strong church leadership in our congregations, our loyalty is ultimately to God. Think of it this way: There are many people to whom we owe great debts. The founders of our nations, great leaders of the past, war heroes, inventors, scientists, even our own parents. We can gratefully embrace the good things they have given us without agreeing with them in everything else.
Ironically, even Catholics can be grateful to the Reformers. As much as they disagree with their theology, it was their drive to bring the faith to the common man that drove literacy rates up, as well as legalised owning a Bible. Catholics are allowed to own Bibles today because, praise be to God, the Reformers won. But just because the Reformers did them some good does not mean Catholics must take them as their new magisterium.
While Christians owe the Reformers a great debt, we did not change out Pope Leo X for Pope Luther. Rather, we recognise Luther for what he was: A sinful man who, by the grace of the same God who saved him, did wonderful things for the Kingdom of Heaven. The same is true for other Reformers, some of whom were more Christ-like than others.
Ultimately, the only way for Catholics to refute the Christian faith they call "Protestantism" would be to attack the Bible. By contrast, Catholicism puts a lot more stock in their leaders. Therefore, Catholicism must answer for its violent history, particularly its assault on the faithful, its suppression of the Bible, and its enforcement of pagan dogmas. Christians, however, have nothing to answer for, because what we do either glorifies God, or was nailed to the cross.