So, after a century of entire societies based on race-based slavery, is legislative and judicial reform going to completely wipe out racism, or is it more likely to be subject to some sort of asymptotic decay? Is everyone going to change their minds instantly about racism, or will it persist in the minds of large numbers of people? Is racism likely to disappear with everyone's logical and rational acknowledgement, or is it more likely to to persist in forms which are deniable and publicly invisible? Everything we know about human nature indicates the latter choices are going to be true.

This is precisely why witch-hunt attitudes towards racism are counter-productive. Racism isn't an evil or a personal shortcoming [1], it's a consequence of unfortunate history combined with shortcomings in the way our minds process social information. Treating racism as a kind of evil makes communicating rationally about it impossible. And since it's a once huge social factor asymptotically decaying, it's going to be all around us. It would be much better for us as a society to be able to talk about it rationally. That's not what the current social climate is conducive to, however.

Basically, everyone's attitude towards stuff like racism and sexism should be somewhat like the stance "Everyone Poops" takes towards, well, poop. It's not the most pleasant thing in the world. It's just a consequence of where we came from. The only difference is that there is hope that eventually we will overcome it. (Well, maybe when people's minds are uploaded into computers, we won't poop or judge people overwhelmingly on external morphology.)

EDIT: [1] - Harboring some racist attitudes or ideation is perfectly understandable, but if you go and perpetrate some sort of crime or act of cruelty as a result, this is certainly wrong. We all experience hate and negative emotions. This doesn't excuse you from acting like a civilized human being.