I think a lot of it has to do with the media. Look at any of the "debates" on any, and I mean any, of the cable news stations and this is what you will see. They don't follow formal rules of debate, they just try to yell louder than the other person. In what world is this acceptable behavior? Look at shows like Pardon the Interruption. First off, can anyone think of something less consequential than a punch of pricks sitting around arguing about sports? This show is exactly like the cable news debates. Everyone yelling so that they can be heard, while nothing of substance is being put forth.
I know I'm a luddite, and I make no bones about that fact. I don't have a blog, because I don't assume I'm interesting enough to justify putting every single mundane event of my life out for everyone to see. I don't have a facebook, myspace, etc. page because I like being able to google myself and only seeing three or four links. I don't have a TV, I don't have a land-line. I only have a cellphone and I screen calls religiously.
I think it's a result of a myriad of different things. Part of it is generational, part of it is cultural or societal, part of it is upbringing, part of it is personality.