But all of racism is based upon the idea of "reasonable assumptions". You don't need to assume. By your logic, stats can inform assumptions about black people being up to some crime, Arabs being up to some terror plot, Indians committing some rape, etc. etc. But the whole point is that one person should not be tarred by the assumptions others make about their ethnicity.

Your question is a trick. If only statistics make something reasonable, then the only "reasonable" assumption is that he is a criminal. And all racist assumptions will be "reasonable". But the very idea that a person should be assumed about based on his ethnicity is not reasonable or morally right.