Man... this guy.
That 'fancy pants writing' won an Oscar.
So what if most of the white people in the film are racist. That's the story. It's his creative license to do it this way.
Regardless, the issue of slavery is impossible to deal with without showing the brutality white people carried out in the name of business. You'd be ignoring a whole chunk of history if you DIDN'T show it.
What you're forgetting is that Samuel L Jackson's character in this is a black guy, who happens to be one of the worst racists in it!!
The biggest supporting role in the film, if not the lead role, is Dr Schultz - a white guy - and his character is an icon of fairness and principals.
The wrongdoing of the racist characters in this film ACTUALLY HAPPENED in history. It isn't painting 'the entire white race' as ignorant and evil at all, because the 'entire white race' didn't run the slave trade. A very small sub-section of it did. Seems you don't understand that!? Read a history text book and you'll read far more extreme race wars than Tarantino depicts here.
It is a massive and powerful statement this film makes against racism.
And don't forget that slavery isn't just about race - it's a class war waged by the rich on the poor and it still happens today.