I quite agree. The humour in "European Vacation did not appeal much to me, but of course humour is strongly culturally bound (only slapstick seems to hit home everywhere in the world). For me a German Comedy is an oxymoron, for example, and for my brother Monty Python style humour is incomprehensibly unfunny.
I think that is one of the reasons why comedies do not cross borders as easily as drama, crime or horror films. I have always wondered, for example, why it was deemed necessary by Hollywood to make US versions of so many French comedies, when I find the French originals invariably funnier (If you speak French, you can sometimes laugh twice, once for the joke in French and once about the translation in the subtitles
), but I assume that the Hollywood versions are more palatable to the American public at large.