Happens all the time. History gets "re-interperted" to fit the present agenda. Usually, the individuals doing the mechinations want to prove something about one group or another. In the cartoons case, it is that the US in the 40s was only marginally better (if at all) than the Soviet Union or the Nazis. Bump into this all the time. Revisionist history seeps into everything.
In short, the cartoons are not watched to understand how a society was, they are watched to use for ammunition to prove a questionable point.
More PC BS.