Ok, catch the stalkers irrespective of color and take them to justice. Make a rule to enforce it. Like they don't break the traffic rules due to fear of fines, they won't break the moral code due to the same reason.

Fact of the matter is... collectively thinking of a nationality or color as bad people is my dear friend Racism... fair and square.

This is something the world learned 50 years ago.
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Quidquid latine dictum sit, altum sonatur.