Okay, so obviously it has changed. They weren’t supposed to be sold, then they were, and now they aren’t. And clergy is a misleading word to use. Even the pope himself was involved in scamming people out of their money for indulgences. I’m tired of this refusal to even acknowledge things that are documented fact. I don’t get how you could say that “nothing’s changed there,” when the practice has been different depending on who is in charge. It’d be like if I said that black people (or black men anyway) in the southern United States were able to vote ever since Reconstruction because of the 15th Amendment. Nothing’s changed there, now we just have the Voting Rights Act. It’s really misleading because yes, legally blacks were allowed to vote, but it was common practice and basically the law of the land in racist southern states to deny them their right to vote. So no, it actually has changed.
My point is that the teaching of the Church hasn’t changed. The abuses have. There is an important distinction to be made between the teaching authority of the Church and the people who belong to it. When someone says “the Church teaches…” they are referring to the former. When someone says “the Church permitted abuses such as…” they are referring to the latter (i.e. Church officials). In other words, it’s a dichotomy between doctrine and policy, the former of which is unchangeable, the latter of which can. Policy itself is divided into official Church policy (e.g. the contents of Canon Law) and individual policy (e.g. how Church officials handle sexual abuse cases). It is only in the latter that abuses arise, and they have no bearing on what the Church actually teaches, and can in fact run directly contrary to Church doctrine.
TL;DR: The teachings of the Church haven’t changed. Policy, whether unofficial and individual or official and codified, has.