So you assume the RCC sinned?
Actually, yes and no -
I remember the efforts of pre-Vatican II nuns teaching in Catholic schools, and the tyranny involked, and the usage of guilt to motivate kids - Which is not theology class, mind you... Yet nuns are not necessarily good teachers, especially in classroom environments... They were punitive and repressive... Plenty of sin simpy in that...
And I suspect that you were educated in this old system, which is no longer all that much a part of Catholic Education - For even if nuns are still employed, they are not the hard-disciplined elder toughs that ran roughshod over the kids in the '50s, nor are they the "black and whites" with hoods and attitudes... They have moved on... RC monastics these days do not wear habits all that much, and the one some wear are pretty tame by the ascetical standards of yore...
The point is not that the Church has changed its point of view to agree with your personal opinions, but instead it is that whatever the Church has done does not matter insofar as your profound and personal NEED to grant them forgiveness is concerned, and this, I suspect, you have not done, because you are insisting that they change the Theology of the Church to your and Luther's point of view... This is a child's demand...
You see, you WANT this FROM them... They only want you to become their disciple and submit yourself to the authority of the Latin Church, and if you say no, they will acquiesce to your decision...
Not so is the matter for you, however, yes?
YOU want THEM to CHANGE to YOUR theological opinions...
And it simply does not work that way...
Now I don't agree with a whole lot of their theology either, but their decision to believe their Church's views is not a bone in my craw, as it so seem to be in yours... But you see, I was not a little kid under mean nuns who bullied me and taught me things that proved later to me to not be true... I am not a child resenting Church Authority that I think LIED to me about ultimate things... So it is easier for me to step back and not wear my hurt child feelings on my sleeve and just attack them as if I were some antifa hate-spitter...
You need to forgive them, and not only that, you need to thank God for giving them to you to lie to you, if that is what you think, or for whatever wrongs they inflicted on you in your student's perspective of those formative years... But as a bare minimum, you must forgive them all, remembering each face and each event of transgression...
It is anathema for your soul to harbor such great resentment, my Brother... It will eat you alive...
"Forgive us our trespasses,
as we are forgiving those
who are trespassing against us..."
And please forgive me for presuming to speak with you here this way...
Forgiveness should be our way of life in ALL transgressions...
Arsenios