And if not, what might it be about this sub-group of people that will never ever "get it" - what's different about them that they simply can't?
I like to think that I am rational, but I still double check myself to make sure I'm not being sexist. Occasionally minor sexist behaviour or thinking still creeps in...
I'm not sure if delusional is the right term - small minded might fit the bill a little better. So if it's due to mental laziness or an inherent dearth of mental ability, perhaps bigotry is difficult to abate without laws to protect minorities.
Nonetheless you ask a good question - with time and exposure can we eliminate bigotry? I hope so. But it's easy to invent new targets for ridicule: Emos, Hipsters, Rockabillies etc. They're not exactly unprivileged minorities, but it shows how easy it is to disparage someone because of their appearance and cultural differences.
I think all of human history shows your hope to be misplaced.
What evidence do you have that humans would reach this lollipop level of appreciation and understanding, even in geologic time? Genocides occur even today between peoples for reasons that many even educated people have difficulty deciphering. As well, go look at the comments on YouTube and see if humanity is advanced. I mean really ...
The reason I asked that particular question (and I guess I didn't do a good job of it), and used the word "delusional", is because I personally think there are in many cases vast differences between sub-groups, and these differences are of varying incompatibility. Many of them are imagined (false stereotypes), but many are not, and I also find it naive, this idea that all we have to do is pass some laws to force integration and then suddenly everyone is going to see the hateful errors of their past ways.
As you correctly point out, there is a lot more in history to suggest we cannot "all just get along" than there is to support a unified utopia. Also, in politically correct forums such as these where most participants have a much less diverse background than they'd like to think, there seems to be this pervasive idea that the fault lies all on one side. Listen to some rap music, or go visit one of the more extremist feminist forums, or an atheist forum, where the participants really speak their minds, and you'll see there is plenty of irrational bigoted hatred everywhere, not just from the privileged white male.
To me, the idea that you can solve a problem when you insist on being ignorant of many aspects of it is rather foolish.
"In sufficient time," perhaps. In the meantime, millions of people are marginalized, exploited, abused, and killed. Those are real human beings, not just statistical stairsteps to Utopia, and I'd prefer to let them have freedom and equality now rather than reserving it for their great-great-great-grandchildren.