It's playing on stereotypes in a humorous way. Stereotypes tend to be based upon
perceived majority opinion, it does not make them 100% or even 50% accurate. The humour is meant to make you laugh by considering your own experiences and opinions, and laughing at yourself, more so than the 'target'. Much humour (higher-end/non-slapstick) works in this way.
People didn't laugh at generations of Irish jokes because they considered the 'line' suggested was a realistic or true one. Ditto re: the Germans and Polish jokes. I'm sure many countries invoke a neighbouring country, as a comedic figure of fun...
p.s. and no, many westerners can't 'take chili', but it's more as it is totally outside of the culture. *Even if they could they wouldn't wish to*. Same way as my SGn mother-in-law refuses to eat anything that
isn't spicy (when she's in Europe she even carries sachets of chili sauce in her handbag, to liberally douse everything with

).
Would you like to eat a ham joint wrapped in waxed paper and hung off a beam in a barn for 2 years until it's essentially rotted to a solid 'cured' mass ('old ham')? Or, sour cream + salt oat porridge (rommegroet)? Or cheese that is so stinky it would knock flies out the air from 5M and you have to keep in it a sealed jar (gammelost). Japanese natto, live 'drunken prawns' or sashimi off a still breathing fish? ... the list goes on
p.s. Apols, I went on a bit longer than I expected and sound very earnest. Nothing personal, I just got into a groove...
