Certainly God's providence operates despite - even through - the actions of men who choose to exercise their God-given free will in evil ways.
Exactly. which is why this arguement is starting to get down right silly. There have always been sinners. There have always been evil people in places of authority, be it Churches,government, etc. It will continue to be so until Christ returns and sets up His Kingdom. And yet here we all are, regardless of whether or not we are Protestant or Catholic, for the most part, the most important things that we need to know about Christ we all generally agree on. And yet, we will find any little, or big, difference to argue about, instead of focusing on what we do agree on. For the record, I was raised Baptist and became Catholic as an adult. But for as long as I can remember I have been a Christian. And I will say something else, there are a lot of misconceptions on both sides of this debate about one another and what each of us believes. Just because one Pope, or maybe many, did evil things, does not mean every member of the Catholic Church is evil. And just because some, or many Protestant leaders have done evil things does not mean all Protestants are evil. And I get really tired of seeing people paint religions with such a broad brush. The fact of the matter is, all of these groups are made up of individuals, and individuals sin.
I understand your frustration. It is certainly true, as you say, that "there have always been evil people in places of authority, be it Churches, government, etc." No organization of man is immune from this reality. The reason that many non-Catholics beat the drum so loudly on this issue relative to the RCC is because of the claims it makes. It claims to the the one, holy, apostolic church, and considers its traditions and teachings infallible, equal authority with the Bible.
If it weren't for the fact that such claims belie the abuses that parallel this church for the entirety of its existence, non-Catholics would find no reason to dredge up this history. So long as these claims are made by this church, there will be a chorus of detractors pointing out the hypocrisy of its claims.