Assuming it's true, learn to deal with it and put it behind you. Go on with your life. I suspect that's what most people would do with a similar history.
But with the acting career dried up, why not drag the whole family through the mud to make a few bucks. Nice.
To normalize it. This may not be MacKenzie Phillips' intention, but it's Satan's intention.
Get stories like this on daily talk shows, the nightly news, in movies, "thoughtful" or "hard hitting" documentaries, and gradually we will begin to "understand" perversion. Throw in support from "experts" in psychiatry, medicine, anthropologists and science and we will begin to rationalize perversion. Liberalize the churches to eliminate any opposition from those who "hate."
Worked for homosexuality. Took only four decades of concerted effort.
Poke around a bit, and you'll see the beginnings of the normalization of pedarasty and consensual incest.