For example the Dutch took over a large portion of central Africa in the 1700-1800s (roughly). He set up work camps, (aka slave camps) and worked everyone killing thousands upon thousands.
I guess I can see how a racist would see that as an improvement.
And this is different from the rest of African history how? Heck, the Bantu tribes have massacring the pygmies for hundreds of years. Muslim raids on European coasts all the way up to Ireland resulted in the taking of over a million slaves, most of whom were worked to death. Similar raids were mounted by Vikings against Saxons and vice versa. Slave raids, massacres and so on - all are part of the complicated fabric of history. As someone who's read a fair number of Chinese histories (hence the Internet alias Zhang Fei), including by John King Fairbank and Jonathan Spence, I can tell you that every change of dynasty in China involved the deaths of up to half the population as a result of the civil war, partition, foreign invasion, famine and plagues that followed. And they were the lucky ones. Europe had it much worse - with serious conflicts (Hundred Years War, anyone?) and slave raids wiping out ethnic groups and keeping the population at low levels until pretty much the beginning of the renaissance. Note also that the Dutch used similar measures against conquered populations elsewhere, including in Batavia (now Indonesia), and yet African crime rates are many times those in Indonesia.
Ultimately, your issue is denial. What you're missing is that in aggregate, the races are different in the same way that various breeds of dogs are different. While there are slow greyhounds and docile pit bulls, they are the exception to the rule - on average, greyhounds can run really fast and pit bulls are pretty aggressive. Obviously everyone is responsible only for his own actions, but the reality is that a random white stranger is less likely to be a criminal than a random black stranger. This is why Jesse Jackson, in a moment of candor, said that when he's walking on the street at night and hears footsteps behind him, he's generally relieved when he swivels his head and sees a white person. The black colleague you know and like isn't a criminal. But the random black stranger you encounter on the street is 6x more likely to be one than a random white stranger.