Why are americans so naive about australia?

i have often heard of americans clifying aussies as 'convicts'. are they really that naive about australia? i've also seen comments on here that refer to australia as being a 'dirty' country. are they not taught australian history in schools over there as we are taught about history of their country? i get the distinct impression that americans in general have a much lower rate of intelligence than aussies. they think we have kangaroos jumping down every main street. is that the impression we give them? or are they simply just not interested in truly educating themselves about aussies and their culture? i often have to laugh at the lack of knowledge they possess