SF0--
Part of the issue may be that the construction of the concept of racialized differences used scientific studies that 'proved' the inferiority of some races relative to another.
A second part of the issue may be how we Americans approach knowledge in general, especially if information is being presented from experts to laypersons. As an example, I would point to the resistance I encounter when I suggest to people whom I know that they come to a BB such as this one to learn more about the American armed services that they so casually vilify.
A third part of the issue may be that even when confronted by a scientifically verifiable piece of information, some may still decide to favor other sources of information and teaching. Recently, HBO aired a documentary on Morgan Freeman's effort to subsidize a single prom in a small town in Mississippi.
The documentary, Prom Night in Mississippi <<
LINK>> features residents offering their views on race and race relations. While some residents were open to the idea of a single prom, others remained skeptical.
Some of these skeptics focused on factors such as how they were raised and their faith as Christians, and simply how they wanted to live their lives while also acknowledging their understanding of differing viewpoints. Given a wide range of information, residents of this town, like people elsewhere, made their own decisions for their own reasons. Such is life.