Why is the book Unwind a dystopian environment?

A good working definition of a dystopian society is the following:

A futuristic, imagined universe in which oppressive societal control and the illusion of a perfect society are maintained through corporate, bureaucratic, technological, moral, or totalitarian control.

I will get to a few specific characteristics in a moment, but let's unwind the above statement and compare it to Unwind. The book does take place in the future.  It's not a far off future, but the book does make it clear that technology exists that does not exist currently.  That technology is called "neurografting."  That technology allows doctors to use every part of a donor for transplants.  Our current technology isn't even close to that.  We can only currently transplant 25 different tissues and organs.  Because the book is set in the future, it is imagined.  

The second part of the definition talks about societal control through various methods.  No matter which method is used, the method will almost certainly use propaganda.  That is true in Unwind too.  The people have been convinced that unwinding is moral and humane.  It's even protected in the "Bill of Life" and states the following: 

However, between the ages of thirteen and eighteen, a parent may choose to retroactively "abort" a child . . . on the condition that the child's life doesn't "technically" end.

How the people in this future society have come to believe that an aborted, unwound child isn't dead is beyond me, but they have come to believe it.  They believe it because the only information that they are given about unwinding is positive and glorious information.  Take for example this line of logic from Samson Ward. 

"I was never going to amount to much anyway, but now, statistically speaking, there's a better chance that some part of me will go on to greatness somewhere in the world. I'd rather be partly great than entirely useless."

Another standard dystopian characteristic is that citizens often live in a dehumanized state.  That is sort of true for this book.  Not all citizens are treated as less than human.  Only teenagers between the ages of 13 and 18 are dehumanized.  At that point in a person's life, he/she is nothing more than a vessel carrying spare body parts for somebody else.