Part of what causes racism is those who research the concept of 'race'. Half the time the requesters for some odd reason perpetuate stereotypes in an attempt to get some unknown result.
I've been dealing with the issue of "race" since the early 1960s and I think you might be "projecting" your experience as a Turker to the wider population of Americans. Throughout my life I've known scads of people who were or are "racist" without ever having taken a survey or poll on the subject. (Well, maybe one or two, but that isn't enough to perpetuate "racism.")
More often than not, there are a LOT of issues involved in why a person is racist or not (some "open." some hidden). For instance, the simple concept of "other." So far as I can see, there is no
rational reason for being racist (although those who *are* racist believe what they believe
is based on "rational" argument).
My apologies for such an "involved" couple of paragraphs.