Stereotypes persist because in some way, however small, they are true. This is an accurate observation, so broad, that it defies Weber's model of ideal-typical cases. Why? For all the examples of a stereotype that may be true, there are many more that invalidate the rule.
One of the persistent stereotypes of black folks is that we love watermelon. The racist white gaze of the antebellum period conjured up this notion. It continued onward into the future where whites lessened the gross blow over time; but the stereotype still persists. There are black folks who proudly announce that they love watermelon without any shame at all--to hell with anyone who tells them otherwise.
wattamelon ice cream roll"--what heaven it is--but to sit down, chow down, and eat some watermelon (with the obligatory fried chicken) in public? Nope. Ain't. Gonna. Happen.
Our tax dollars are hard at work folks. Apparently, the USDA has determined that watermelon is most popular among our Asian brothers and sisters. Riddle you that one. Forget the model minority myth, it should be the eating more than all others watermelon myth that in fact stigmatizes our East Asian brothers and sisters.