Well, then, you should read the chapter at least before defending it. There is no suggestion in the chapter of any "reprehension" you should have toward the character, no explanation of why he did what he did, why nobody thought it was odd, nothing at all. It's just there, as if Webb was thinking about doing it and thought it would be fun to write it.
Because, as a writer, you must understand that you can't write something down if you haven't imagined it first in your head. You can't write what you can't think about.
Sure, you could totally disagree with something a character does -- that's true a lot of times. But if I write about a child molester, i'm doing it based on what my brain has absorbed over the years about child molestation. I've read what they do in the papers, seen it on TV shows and in movies, and I can write about it.
Name me one place where Webb would have read about or otherwise been introduced to the concept that a father would pick up his naked son and perform a sex act on him in public. It makes no sense, it's not something I've ever heard of, which is why it seems to be revealing of something in Webb's brain that just isn't quite "right".
Because he was able to imagine that happening, thought it made sense for the character to do so, and didn't expect the reader to be grossed out or to gain a harshly negative view of the character as a result of it.
God forbid I should do anything to defend Webb, but ...
almost 30 years ago, as a youngish Episcopal priest, I was suddenly confronted with a family crisis involving a long long history of father/daughter incest with both daughters AND alcohol addiction.
I needed all the information I could get before I got into this situation. I went to the local NOW office. They had the most extensive library of sexual abuse and perversion and all that in the area. I gave them a donation (all the while holding my nose, but they WERE inadvertently serving a good cause that day). I sat down and read as much as I could as fast as I could about father/daughter incest.
I learned way more than I wanted to know.
Or ask me about, of, I don't know, say how about the couple who tried to strangle their child. I have a lot of things roaming around the old cranium that I didn't really want to be there, but, well, compost occurs, y'know ....
I don't know how Webb could have come across this nonsense, but, well sometimes you learn stuff or see stuff you had no intention of learning or seeing.