we did oppress many races in our pursuit of freedom (irony at its best/worst), so we should be overly-sensitive to how our actions can affect those around us.
As long as people are different, as a whole we all will always have some sense of gravitating towards those who are similar to us, and seeing those who are different from us as such. So there will always be some sense of "discrimination", "racism", "bigotry", etc among groups - it's human nature. This is especially true when individual people re-enforce stereotypes.
With that being said and with all due respect to everyone here, it's time to put the whole guilt thing about what happened hundreds of years ago aside IMO. Some bad things happened in Africa, the US, and elsewhere throughout the world hundreds of years ago. And those things continue to happen in Africa and some other places, although they were outlawed here 150 years ago - long before any of us were born. I refuse to take blame or responsibility for what people did here hundreds of years ago, and I think this is an important hurdle to get past for the sake of true equality.