Correction: It IS a 'culture gap,' not a stereotype.
While there can be culture gaps when dealing with British and American humor, it's not going to be anything like the culture gap a Westerner experiences when trying to deal with Japanese comedy (especially in translation, or untranslated). There's a long tradition of Americans finding certain forms of UK-based humor hilarious.
Also, I find it
extremely dishonest that you attempted to argue that your appreciation of Monty Python indicates that culture gaps cannot affect appreciation of humor when you are someone who has lived for any period of time in the United Kingdom. It is not at all shocking that someone with direct experience of life in the UK would find a UK-based comedy group quite funny.
It's not the culture that makes them funny, it's whether or not they are considered by someone funny, so culture does not matter.
This argument is incoherent. The idea of a culture gap is that people sometimes find humor that originates in other cultures difficult to appreciate, because they do not understand aspects of the culture that the humor is referencing and do not have the day-to-day experiences of someone of that culture.
Frankly, your participation in American and UK-based cultures probably does make you more inclined to like American and UK-based comedy. It also makes you more inclined to like comedy written in English that originates from other Anglo countries like Canada and Australia. You probably appreciate Mexican and/or French humor less, provided you don't speak those Spanish or French. It's hard to laugh at jokes you can't understand.
In fact, "It's hard to laugh at jokes you can't understand" is the essence of the culture gap argument. If you don't know what natto is, then you may not be able to understand a joke about it, no matter how funny that joke may be to someone who's eaten or seen natto before, or who understands how natto is made and what types of Japanese people tend to eat it.
And to me, good humor spans to being clever without relying on that argument to keep it funny.
It is certainly possible to laugh at a well-written joke that originated in another language. For instance, you might laugh at a natto joke if it was translated such that you understood it was a joke about a "gross food" comparable to, say, the way haggis is used in Anglo jokes. If that joke is about natto being fermented, and you cannot possibly infer from the gag that natto is made by process of fermentation? You probably won't find that joke funny, because you will not understand it.