People can learn from history, but many don't, can't, or would rather just forget about it and move on with their own ways. These days the KKK's view has not been obscured from the past, but contains a clearer message about what their goals are, instead of just hurting and/or killing black people and burning churches. They have had and still do have a purpose for their ways, and they became the Klan to fight for it. Their views on things today have very little resemblance as to what they used to be (at least they do not seem like they would be so abusive and hurtful) and all of the actions that they do have different intentions and outcomes, sometimes offensive and harmful, other times not.
Picture yourself in the southern states, in the late 1860's after the Civil War. The "Yankees" have invaded everywhere, taking what they wanted, destroying anything they wished, coming and going as they pleased, and even on some occasions digging up family graves to find treasures or jewelry to sell for money, or trade with soldiers for other valuable possessions. Additionally, everything having to do with State Government that you have grown accustomed to has been shattered like cheap glass, and has been refurbished with armed soldiers stationed everywhere. They restrict any white southerner from voting for anything; the only people that were allowed to vote were uneducated ex-slaves. On top of that, they were only allowed to vote if they voted for the party that was in charge. If they did not do so, they would be tortured, or lynched sometimes both.
To go along with all of that, there were ex black slaves being taught how to kill by carpetbaggers. To the ex slaves it was like a form of revenge towards their former slave-owners to get them back for how awfully they were treated in the past when they were slaves. The blacks would do almost anything to get back at them; rape women, destroy personal property, destroy anything in general, and even kill anyone that stood in their way.