Jerry,

I dunno.. to be sure diversity can be divisive, but being different in and of itself is not divisive ( in a bad way).  Though, I do think you hint at the gross part of the problem. Being different can be tolerated, but that has somehow equated to being lazy/ stupid must be tolerated ( as that is different).  And it is with that, the problem grows.

Also while there is "new" divisiveness, I an not sure it emanates from being different, instead I see it coming an extra pre-wwii work/life ethic push-back. I would call this a "Christian work ethic" but that label pushes emotional buttons, and is not really accurate anyway.
I thing we can all agree that - back in the day- a community would need to pull together each helping the other in their strife against the (generally nature)  economy. Somehow that ideal is completely wiped out, gone... unknown.. and in its place is the idea that I am competing with everyone else. Its "get while the getting is good", 'win at all costs", "due unto him, before he does unto you"... TV is pervasive in this... and children watch this.. absorb this... live this. I personally know people.. that truly believe_ "I am not guilty if I didn't get caught". Flip this around then... I can do ANY evil deed, and if I am not caught... no evil was done. If no evil was done... why would I feel sorry?  This is the pervasive truth of TV, and of children today. Criminals are sorry... sorry they got caught... not sorry they did the deed. Why should they be? TV teaches... innocent until proven guilty... well first you have to get caught.. till then your innocent.
I find the same "wrong thinking" with those new to America. They equate what is "right" with America, with the government. But fail to realize that people make up that government, if we each act only in our own self interest, then the our system of government cannot work. Laws did not America great, people did. Laws don't make people nice, people do.  

/whew.. rant off..