I think he's commenting more on...where to draw the line? The line between what's right, and wrong is getting increasingly hazy...in this Do-Whatever-You-Feel world.
First it was wrong to be homosexual. Now it's okay.
Now it's kinda wrong to be a polygamist, but that's becoming more acceptable.
It's wrong to have sex with family.
It's wrong to have sex with children.
Did you know that there was a psychologist who has suggested that a consensual sexual relationship between father and son could be healthy? If your gut balks at that...remember, guts balked at homosexuality 50 years ago. So, what will another 50 years bring? I think that was the point of the article.