This week a student needed an explanation of positive racism, after being criticized for praising Jews as "good with money". I explained blood libel & the origin of the stereotype (brutal acts of social exclusion compelling the construction of separate systems), but the whole topic led to her asking about other times she'd praised groups holistically--all positive racist remarks, too.
Many of us don't realize how much treating demographics as hiveminds, even when intended "nicely", can do harm.