The linked review is quite good, and the book in question raises some points that should be discussed on a wider platform. Unfortunately, flagamuffin's quip above perfectly exemplifies everything that is wrong with politics today and the very basis for the claims the author makes in his book.
The primary issue here is that a significant portion of the populace is mired in fundamental religious intransigence and political demagoguery. They are fed a constant diet of half-truths and outright fabrications, then naturally use those experiences as the basis for their votes. They vote with their feelings and (mis)perceptions of candidates and issues rather than on facts.
This nation is founded on the idea that its citizens are informed enough about major political issues to vote in rational manners. For example, Jefferson wrote, “If a nation expects to be ignorant and free, in a state of civilization, it expects what never was and never will be.” Alexander Hamilton lamented, “The people commonly act more from their feelings than from their understandings.” John Adams wrote as much, “Evil, in humankind, lies in the lack of governance by reason over the passions.”
Ultimately, it is a fact that un- and misinformed voters are a major problem for us as a nation. Masses on both sides of the aisle exhibit the trait of refusing to take in new information and use it to modify their world views. However, this phenomenon disproportionately affects the people that self-identify as Republican. Reactionary, self-congratulatory platitudes like that which that above only serve to entrench that kind of mentality.
I'm not writing to defend the book. I find problems with it, and truly I have deep moral and practical concerns of what it would mean to attempt to restrict voting privileges. But I do think there is something deeply concerning with the fact that we have a huge percentage of people and politicians who are completely ignorant of the fields they command such as commerce, health care, the internet, and the environment; and worse, who deny basic scientific evidence in those areas and more. They aren't just ignorant of such things -- they are willfully, pridefully ignorant. They are either unwilling to put in the work necessary to educate themselves or unwilling to have their self-identities challenged in that they may have to change an opinion. Again, this trait disproportionate affects Republicans, who by their very nature cling to traditional attitudes and are reluctant to change.
For these reasons, I also reject any notion that voters don't need to be informed, i.e. that it's perfectly ok for people to vote selfishly. To do so ignores the fact that each of us occupies a very tiny part of a very big world. To live and vote like that requires an enormous faith in the political system that it will compromise the selfish desires of each constituency. Yet you will not have a functioning political system worthy of that faith if short-sighted buffoons are the ones running it because you put them there. Mass blocks of un- and misinformed voters turn political contests into cults of personality - giving jobs and publicity to who-ever says the most outrageous shit, who has the most charisma, who deals the sickest burns. Those are not character traits we need in our elected officials.