I find it interesting that in fifteen pages of discussion about religion, there has been no mention of God. Seeker, that might give you your answer.
I understand the bewilderment of seeker and jenny60, and their frustration. They naturally think that if this was a scandal in a gym, or a political party, or a golf club, or even a government, that members of the organisation should just leave, refuse to pay their fees, and protest. I would agree, but there's another element here that defies logic.
I don't want to be patronising here by saying "oh, you don't believe in God so you couldn't possibly understand"- but I think, to help give you your answer, faith is at the heart of why Catholics don't just turn their backs on the Church.
For most of us (yes, putting my hands up) our faith, whether it be Catholic or any other, gives us strength, comfort, hope and peace. Usually our experience of religion at grass roots level doesn't involve discussion of "ishoos", and you'll find the majority of Catholics have learned to follow their own consciences and adapt their faith and beliefs to modern society.
Of course we condemn evil in all its forms. Of course we are revolted and disgusted by institutional abuse. Many Catholics have a real crisis in reconciling their personal practice of faith with the abuses of the institutional church. However, we persist, because (in my own view) we believe that God loves us and will help us. It's very hard to reject a deeply-held belief like that.