[user104658]

One suspects that what is being discussed when people say "minorities can't be racist" is institutional racism and, yes, it is arguably true that only white people can engage in institutional racism in Europe / the US (though it is worth pointing out that it does happen with other ethnicities, and against white people too, in other countries such as S. Korea and Japan).

However, institutional racism shouldn't be confused with plain old common racism. Anyone, of any nationality, colour or creed can be a big fat ol' racist.