Stereotypes exist, and people have irrational confidence in the relative spiciness of their culture's cuisine. Unless you have some kind of spice challenge, your food isn't that hot. Just about every wing place in America sells wings that you can order that are just as hot as food you can find at your average Indian restaurant, or Jamaican restaurant, or Sichuan restaurant.
Every job has folk wisdom and heuristics. I worked retail and then retail tech support for years. I've had to deal with plenty of employees who wouldn't listen to customer's preferences because that preference didnt match some heuristic they were using.
They had the same justifications--"They don't really want it, they'll just end up returning it."
Those employees who insited on treating all of their customers like children because of a few bad experiences were consistently poor performers.
Their heuristics were detrimental, but they kept using them because people are very vulnerable to confirmation bias. No mass hysteria required.
Listen to your customer. Give them advice, warn them if necessary, but don't treat them like a child because you once interacted with an asshole who looked a bit like them.