These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
A combination of this, Harsher in Hindsight, and History Marches On comes with Mortimer's comment about how one of his ancestors "scalped the Indians" as proof of how crazy he was...in fact, historically whites DID scalp Indians throughout the various conflicts between them. Actually, scalping was invented by Whites (though some Indians did practice it on each other afterwards). However, since most white Americans didn't know these facts when the movie takes place, it doesn't break the Suspension of Disbelief for the audience when Mortimer tells this story to Elaine.