all negative stereotypes have 'some' foundation in reality, even though they are exaggerated and the source of the foundation is mis-understood by most joke tellers.

with blondes, we get a situation where many shallow, dumb, impressionable women buy into the idea that being 'blond' is the best way to impress and 'get'....and so we get LOTS cases of the saddest behavior being done by, and associated with blonds..(often EXTREME blonds with platinum-dyed locks that get attention if not respect)(Can you imagine Anna Nicole Smith getting her own TV program if she were not BOTH blond and _______?.) It is simply a hook to aid in the over-simplification which so many are drawn to. If a NON-blond does the same thing, you have to work to find another stereotyped category to fit her in, and it usually doesn't carry the same weight.

When I hear a 'blond' joke, I sort of mentally substitute 'shallow, inept, sad creature who doesn't even try to comprehend the way the world works'....(I never took Polack joes seriously either, though there were some very funny images in them)