The lynching of whites occurred for many of the same reasons as the lynching of blacks, an attempt to assuage economic inequality, perceived sexual crime (rape/adultery) or perceived crime. Another thing you should be aware of that the statistics that website is drawing from are those of the Tuskegee Institute. Many of the victims counted as white in those numbers were in fact Native American, Chinese/Japanese or Hispanic. Modern historians of interracial violence are still attempting to figure out the true numbers of those lynched in that period and the Tuskegee numbers have been discounted to some degree.