Your father’s abuse was physical, psychological, and sexual. It was also compounded by your mother’s negligence in protecting you and her complicit agreement with your father’s actions and demands. Your parents’ behavior sounds like it was severely distorted by their religiosity, the excessive belief in a religion to the point where “the bible” or the teachings of a particular belief override or mask pathology. The fact that this was common means by seeing it as “bible study” your parents lost the ability to nurture and protect you properly. Forcing you to do this against your will and shaming you into doing it wasn’t a spiritually wholesome act. What was missing were any safeguards against putting you in this situation. It was condoned by both of your parents, and at that level there is no difference between something extremely inappropriate or abusive. It was pathology disguised as a religious practice.
I am glad you are dealing with these issues now. I know people often say that their parents didn’t know any better or that they did the best they could. But that doesn’t change the fact that their best wasn’t good enough. Often, by not acknowledging the limitations and exploitation generated by abusive parents we can limit our own growth. Seeing it for what it is while having compassion for the circumstances that created it can allow for you to cope more effectively.
I’d encourage you to speak to your therapist about it, if you haven’t already done so.