While archaeologists and anthropologists cannot take the entire blame for the prevalence of racism in our human societies, they didn't help things, at least early on. The ideas of the 18th century Enlightenment reawakened interest in the past, particularly the classical past.
In the early 19th century, these notions were followed with enthusiasm by those folks that archaeologist Roderick McIntosh called 'radical nationalists', early archaeologists who sought to connect the most developed societies of the time (e.g., western intellectual society) with their supposed high-falutin' ancestors. This led to all kinds of awful stuff, like physical anthropological studies comparing skull types to ancient cultures ('low brow', indeed). But, because the physical studies failed so miserably, anthropologists such as Franz Boas recognized that the 'superior race' notion was baloney and like it or not, human is human.
I still don't know why anthropologists can't yell this loud enough for people to hear, but it probably relates to our essentially need to define 'us' versus 'them'.
Sources
A brief bibliography on the origins of race was assembled for this project.
This glossary entry is part of the Dictionary of Archaeology.
