Maybe we're not as different as we think we are.
I'd even go so far as to say we have more in common than any of us even realize any more. We live in a culture of increased comfort, increased choices, and increased convenience. While these are all benefits they all have come at some rather hefty opportunity costs-- the largest of these I'd argue are increased divisiveness and seclusion. The technology that has brought the world closer to us is also the world that is de-humanizing our neighbors, its driving wedges between us.
Think about it... Before cable there were 3 major networks, PBS, and a handful of "superstations" (WPIX and WWOR out of NYC and WGN out of Chicago for example) broadcasting out of major urban areas. Most people who owned TVs, if they were lucky, got maybe 10-12 channels. Many only got the 3 major networks and a nearby PBS affiliate... 4 channels. That means the chances that we and our neighbors were watching the same show on any given night was substantially greater than it is today. That created a commonality of experience and that commonality of experience was a uniting force of sorts. Who cares if our neighbor's politics differed from ours, we both watched M*A*S*H* the night before or maybe we both caught that Dallas season finale cliff-hanger. It was something to discuss that wasn't politics, it was something that brought people together... rather than tore them apart. A "commonality of experience" serves to humanize others in our eyes... it's a lot harder to actively dislike someone (no matter how different that person's politics might be from ours) when we have other things in common with that person. This commonality of experience made for a substantially less divisive culture.
I grew up going on long road trips with my parents. We'd listen to the radio together, we'd talk, we'd play "car games"... We interacted with each other. Yeah sometimes I'd pop on headphones and listen to music, sometimes I'd get lost in a book for awhile... but that wouldn't occupy an entire trip. It would be a brief distraction (there is such a thing as "too much togetherness" after all).
Today many cars have DVD players on the seat backs so the kids in the back seat can watch TV or DVDs to keep them distracted... So Dad's driving and listening to the radio, Mom is checking her texts on her cell phone, the kids are in the backseat with headphones on watching a movie (or possibly even 2 separate movies)... What aren't they doing? Communicating with each other. Dad doesn't have to stop and get out of the car to actually interact with someone else to ask for directions because his Garmin or TomTom is there guiding the way the whole trip. These conveniences that distract us, also serve to isolate us. In our isolation our fellow humans-- friends and family included lose a bit of that humanity to us. Over time we've started to shed our social graces that made us considerably more civil with one another. When we aren't even communicating properly with our own families, how can we be expected to communicate civilly and respectfully with the strangers we come into contact with on a daily basis?
These new technologies aren't the cause of divide, they are merely enablers. We live in a culture of excess. We've long forgotten how to keep things small or simple... everything is to the extreme. So, while these new technologies in moderation provide wonderful new conveniences in excess they drive wedges between us, our friends, and our neighbors. They isolate us from one another and they've caused us to, over time, forget our civility towards one another.