We see exactly this kind of thing today. Think about certain political statements to the effect that "immigrants are horrible people and we should keep them out. if we had more immigration it would be horrible". <today they mean it's bad, not in the past>. "But when my forefathers came here, it was different, we were good people <white you mean?>, our forefathers did all this great stuff. immigrants today are not like that". So it's clear this willful lying to yourself is still going on.
Comparing slavery to any critique of immigration (often about illegal immigration!, not any immigration) is surely a stretch. I am sure there is some non-zero number of individuals who think about some races like slaves still, but it is nowhere near the public mainstream.
I have come to the sad conclusion that overestimating the amount of racism is the safest course of thought. It's my obviously anecdotal experience, but I'm continually amazed how many of the people I come in contact with hold racist views.
