Incest is a form of abuse

It's a means to display power over the weaker family member.
As someone who knows the implications of incestuous abuse I can say that after years of it, you stop trusting any part of your family and start having more trust issues and become suicidal and may almost go insane.

I personally have been clinically diagnosed with Major Depressive Disorder and Generalized Anxiety Disorder.
I have suicidal thoughts on a daily basis and a constant craving for revenge.

I would not wish this torture upon anyone.

For those who wish to understand it, try reading psychology books or if you like movies then I'd recommend the movie called "The Strange Thing About the Johnsons" and another movie called "Cutting Moments"

Both movies depict the mental agony and torture that the victim has to suffer at the constant hands of their incestuous abusers and the family dynamic caused by the abuse. Note that it is not for the faint of heart.