I just read Jacob 3, which includes a stern warning towards the Nephites regarding how they treated or viewed the Lamanites. Jacob was in charge at this point, Nephi having passed on, so they were only one generation away from the original conflict that separated the two peoples. In fact, it's possible that Laman and/or Lemuel were still alive; we don't know. Here's what the Lord says about the Lamanites to the Nephites:
Wherefore, a commandment I give until you, which is the word of God:Consider that generations later, we have a couple of incredible examples where the divide between the Nephites and Lamanites was instantly and easily breached by a simple demonstration of love and service. In other words, the divide was primarily caused by the Nephites' condescension and contempt for the Lamanites--the divide was an imaginary one, in a sense. Once you remove the philosophy that created it, it disappeared.
That ye revile no more against them because of the darkness of their skins! Neither shall ye revile against them because of their filthiness! But ye shall remember your own filthiness, and remember that their filthiness came because of their fathers.Wherefore, ye shall remember your children, how that ye have grieved their hearts because of the example that ye have set before them. And also, remember that ye may, because of your filthiness, bring your children unto destruction, and their sins be heaped upon your heads, at the last day. (Jacob 3:9-10)
This brings to mind what I learned as I studied the Isaiah chapters in 2 Nephi about latter-day peoples. Isaiah names two different wicked civilizations: "Babylon" and "Assyria". Babylon seems to represent the corruption and general pride and wickedness of latter-day civilization. Assyria, while also wicked, seems to be born of the grief and misery left in Babylon's wake--the natural consequence of Babylon's iniquity. And so Assyria, in spite of its flaws, becomes a tool in the hand of God, bringing Babylon to justice by forcing it to face the consequences of its own sins.
I think the same is true of the Lamanites in the Book of Mormon. It may be hidden beneath the various political views of the writers of the Book of Mormon, but the truth seems to be that the Nephites mostly treated the Lamanites with contempt, and God held the Nephites responsible for that. In the end, the Lamanites became God's tool for teaching the Nephites their final lesson: the Nephites' enmity towards a people they should have considered family is what destroyed them.
When you judge someone, remember that the things you judge them for are most likely circumstantial, ultimately caused by someone else, and not really their fault at all. Take the opportunity to remember that your own circumstances may change at any moment and you may end up just like them. And most of all, remember that you may end up being responsible for others' sins if you do not quit being a bad example.