I'm not nearly as averse to "unlikeable" characters as some readers are. People are unlikeable. When I read fiction about likeable people, I sort of have the sense that I'm being lied to, or that the characters are being strategically misrepresented. Not that veracity is fiction's best goal.
There's a lot of other stuff going on in this book. JFranz's stewardship might do the book more harm than good. Stead is much more interested in language than Franzen ever could be. Sam manufactures his family's world using language as material and will as mortar.