Your whole argument falls apart because, first and foremost, everyone is an individual. Some of the most intelligent people in the world are black, and some of the dumbest people in the world are white. But when you say "I wish n***ers weren't so dumb and violent", it passes judgment on an entire group of people and it's patently false. Not all black people are anything. Some black people are total pacifists. Some white people are terrible, violent criminals.
The other reason this argument falls apart is because of socioeconomic reasons. Yeah, violence is the worst in Africa. It's because until the late 1800s to mid-late 1900s, every part of Africa was ruled by European occupiers who suppressed their education and used them as slaves. When they suddenly left, they didn't know what to do. They had gone from tribal living to enforced civilization, to freedom, but freedom within a society model that was not theirs. There are terrible people of every group of humans, and so in many cases, whoever was most violent ruled. So many Africans grew up traumatized from witnessing atrocities, and were press ganged into joining militias and shit. A part of daily life is facing marauding gangs, because everyone is hungry and some people are sociopaths and form these things (and there are some incredibly notable and much more world-damaging and far-reaching white sociopaths responsible for so much death and violence). To say "yep they're just worse than us, WE don't do that" is incredibly ignorant. Yeah, we've had a continuous civilization of our choosing for thousands of years. The leadership and infrastructure of our countries are vastly better than the shambles that European colonists left the African nations with (not at all their fault, they were the victims). And as far as intelligence, IQ tests are known to be quite falliable. If someone has never had any formal education or a habit of higher thought (due to constant survival mode), they're not going to do as well on an IQ test. They may turn out less intelligent even, having never exercised their brains as they grew up as much as we do with our education. But it's nurture over nature, because black people given the same opportunities as other races are able to perform just fine, they just don't have those opportunities in many parts of Africa. The truth is complicated, you have to be willing to see the full picture, not your simplistic reduction to 4 map graphics.
And I agree that racism to some extent is natural. Humans love to form groups, and those who are different can be scary. I remember as a kid in school black people scared me. Of course it was because I grew up with a bunch of white people and didn't really have any black friends, and the black people at school were really threatening to the white people. But they had their reasons. It wasn't right to terrorize me and my friends, but it came from somewhere and the root of that somewhere was white people. If we just raised everyone to not view other cultures/skin colors as something totally different from us, something to mistrust and fear (on all sides I mean, because yeah, there's definitely plenty of black people racist as hell against white people, too, and that is also bad, though more understandable at least), then people would have no reason to view each other as inferior based on such stupid qualities as skin color, and whatever particular culture or religion you happened to be born into, through no fault of your own. I guess what I'm saying is, yeah, some fear of those not like us is an instinctual response, but it can be rained out. We're fully conscious creatures, we don't have to be slaves to our instincts.
I will admit I still feel wary and slightly intimidated when I walk past a black person in the street, and I feel the most comfortable with other white people. I can't help feeling that way a little bit, but I don't hold it against that guy, and I definitely don't hold it against the entire mass of black-skinned people on the planet. To me that seems absurd. I love meeting and getting to know any individual who is cool, and when it becomes personal it's just about them and their personality and our interactions. Skin color does not factor at all into my personal interactions with people.
I think it's perfectly feasible to end racism, but it has to be done through exposure and education from a young age.