As the author said:
"In it you'll see an area where I've explained the protagonist's background. Some people don't like it there, others say they wouldn't have liked the protagonist if it wasn't there. I'd love to know which way you feel."
I think it's a concern that's prevalent with authors of dubious or otherwise unlikable characters. So they dump a ton of sympathetic back-story right from the start, because really they just want the readers to like the characters as much as they do.
Thing is though.... an info dump probably won't make people like your character. In fact, odds are that if the info dump takes place in the middle of something interesting (say a murder/theft/hit, since we're in dubious character mode) the reader will just skip until they get back to the interesting stuff.
Or... well... they could stop reading if the info dump is done so clumsily that it stands out like an eye-sore. As they usually do. Best case, that's all they do. Worst case, they break the suspension of disbelief you've just established. So where would it leave your story then?
Nope. Back-story dumps just aren't worth it.
So what if the readers don't like the protagonists? you might ask.
Well... here's a bit of a shocking thing to know: Protagonists don't have to be all that likable. They only have to be interesting to be liked. Which means that if you start with the character doing something interesting (maybe adding a few sympathetic hints here and there) and keeping info dumps out of the opening, you're set for long enough to start bringing out the sympathetic aspects to the character.
But I repeat, info dumps won't let you do this.
Trust yourself, writer. If you know you have an awesome character, trust that you can keep the interest going long enough to make the character liked. I've done it for entire books without explaining the character's motivations, so I can tell you it's possible.
And you know the best part about not info dumping all over my dubious character? He might not be likable, but he sure as hell is memorable.