I'm not talking to you, gentle reader, but to authors. Two authors specifically, but others have also crossed the line. What line? The line between writing and yelling, between forcefully making a point and polemic that hurts to read.
During my recent Winter Break, I read Doctorow's Little Brother and then recommended it to Thing Two. His feeling was that the points being made (about security and privacy) were being made Forcefully, and that perhaps he (being almost exactlly my advanced age) was not the intended audience. That ties in to my reading of the book: its hyperbolic stance on privacy and the overreaching of government agencies in the name of security are intended for a younger audience, and one that is less well-informed about what's going on in the world today. Goading readers into being informed and involved does not always make for a good read.
The other book was Lionel Shriver's So Much For That, which I actaully could not finish. The characters appeared to exist only to advance his cause (the inequities of the health care system), with diseases and problems so intense that they couldn't possibly have been created for another reason. There was no moderation here, no character that made me, the reader, feel that I was seeing the action through their eyes. Instead, the constant lectures made me run as fast as possible to another, calmer read.
I'm not saying that having a cause, or that the need to inform/cajole is a bad thing when writing. But to me, the best books are those that don't make that their only raison d'etre. Those books that do owe their lives to a cause don't feel organic, they feel forced. The characters are there to serve the cause - rarely living in my mind as I'm reading.
So please, authors, if there's something that you desperately need to convey to your readers, consider waiting until a story happens; hammering a square character into a round plot just leads to dead trees and weary readers.