An interesting question; are stereotypes rational or are they rationalizations?
More to the point - if these rappers now have the money, what makes it “Jewish money”? Isn’t it “black money” now? Even more to the point, money circulates. It would be consumer’s money which they paid to someone who then gave it the rapper. Soon it will belong to gold chain makers, Gucci and Bugatti (just a joke about the stereotype of rappers!).
Stereotypes are nothing more than generalizations.
Generalizations can be either valid or invalid. We use them everyday. If they are fair based in facts people regard the generalizations as valid because theres truth behind them. If they are unfair based on lies people regard them as irrational and deliberately unfair and misleading.