Is this the point...?
Is this one of those stories where the bad guy gets away with it? I was kind of reminded of A Clockwork Orange, where because of belief in therapy, the bad guy prospers.
Ted Danson is still being manipulative after he gets caught, such as in the scene when he tells the wife she doesn't want a divorce and end up struggling like one of her friends who got divorced. He even does a 'you don't have to answer now' move, knowing that just by getting her to consider it he's won a massive victory, having opened the floodgates of doubt and emotion that shoudl be closed. Text book manipulation.
The movie I think is showing how it can and does happen in real life that a monster could get caught and still walk away scott free. You get a manipulative and evil but charming and successful dad. A screwed in the head mom. Remember how she is jealous of the daughter, saying something to the effect of 'He went after her because he obviously wasn't attracted to me anymore'. Then you just need a court appointed psychologist who himself is either a psychopath or got his degree by sending in coupons. I mean, he says the molestation isn't about rape, but that the rapist is really just looking for warmth (he literally tells the mom this) and implies it may stem from her going back to work, and that we all have fleeting incestouos thoughts (uhhh, no we all don't!) and the rapist just so happened to have something push him across the line we are all teetering on. Then you need the teen to feel guilty and there you have it.
I know the natural response is to be disgusted at what happens, but it really is a cautionary tale. There are women out there like Meryll Streep, but even worse. They not only stay with the abuser, they help him hide it. This does happen. There are psychologist who are woefully inadequate and give horrible advice that people and the courts take. This happens. Victims feel bad for gettin their abusers in trouble and forgive them, thinking of happier times. It happens. Courts get so overwhelmed with cases they're willing to take plea deals they shouldn't because the kid might just refuse to testify and they won't have a case at all then and maybe if he goes to therapy it may do some good. It happens. A man who gets caught raping his daughter can get off and continue raping her with justified impunity. Horrifying, but it happens.