I think that the question is fairly self-evident...
Does anyone have any answers to this (please, no out-right anti-Catholicism and the like, as I'm looking to see how the change occurred and not just to unleash a load of "POPERY!!!!!!" type comments)?
Society in the west had achieved a great deal of order, purpose, light, due to the spreading of Christianity, relative to previous ages. Heresy was considered to be a great evil-dangerously destructive to all that had been gained for man. The church handed public heretics over to civil authorities in some cases, who would then perform the execution. This relationship between Church and state was obviously very strong, and considered crucial at the time for the good of all even if it was ultimately learned later that such a connection was unhealthy for other reasons. But the whole immediate world was Christian back then, and growing, while enemies to society and the faith abounded outside its borders.
Now, times change and times change
us as our own situation changes. IMO the light of the gospel is largely responsible, behind the scenes, for the great strides in civil rights and social justice matters that have blossomed beginning especially in the west. Knowledge has increased at the same time and, while the Enlightenment wasn't particularly enlightened in many ways, with humanism being a sort of narcissistic and myopic endeavor, it was nonetheless a necessary step involving growing pains for humanity. But when that knowledge is also coupled with humility and the truth and love revealed to man via the gospel, then light increasingly grows in our world even as darkness will always be there to oppose and grow alongside of it.
The point is that substantive change takes
time for both individuals and society-it's a process-and real, positive change is only possible with the help of God's revelation and grace. And I believe that the time has become riper in the last couple of centuries for that light to take greater hold-and by no means has the Catholic Church been the only participant in any past alleged abuses; the Protestant Inquisition, for example, was a
very widespread and ugly affair and also human rights in general were much less enforced than now (think sweat shops, slavery, the exploitation of labor, women's rights, etc). And at the same time, throughout church history altruism was valued as never before: feeding the hungry, clothing the naked, schools/education, hospitals, orphanages, etc. Either way I believe that we're perceiving more and broader genuine compassion, mercy, and the love of God in general flowing through many Christian Churches nowadays than ever in the past. Much of it has to do simply with better understanding and heeding of our own gospel.