Why aren't we over racism?

Consider this story here where an interracial couple is banned by a Kentucky church (yeah, hard to stop stereotyping Kentucky as racist after hearing racist stories from there over and over)...obviously, there are thousands of examples of racism in the U.S., on a micro and macro levels.

In sociology, we always seek to figure out why something remains within society…that is, why won’t it go away…Durkheim, for example, said that ‘nothing that remains for centuries is irrational’ when speaking of religion but, clearly, we can disagree with this notion…I mean, I certainly disagree because much has remained through centuries like sexism or racism that isn’t rational…but what is its utility? What is the reason racism remains? It’s not just about ignorance or whatever…people say categorization will always exist…fine…but will categorization with value attached to one group over others always exist?