I don’t even agree that that qualifies as casual racism.
People in the survey were given a multi-point scale (strongly agree/disagree style) on questions like: Does the existence of racism make you angry/not interested/glad? Now I don’t have the raw data in front of me, so I’m not sure how people answered this particular question, but people who are glad about racism are racists. I’d even say people who deny the existence of racism and/or acknowledge its existence but don’t bother to care are racist. IMO the questions in the survey were good enough to measure some degree of racism. Now there’s methodology and honesty and all that too, but apparently someone gave racist enough answers or they wouldn’t have been able to come to any conclusions.