Why was the Stepfather always whistling like Foghorn Leghorn

I wonder if the Stepfather character might have been inspired by the Warner Brothers cartoons. Foghorn Leghorn was the only other film character I know that was a Stephen Foster enthusiast and was humming “Camptown Races” all the time as he walked. Also, Foghorn was some kind of a “father figure”. He called the younger characters “Son”, and was always giving them fatherly (though often unwanted and unsound) advices. Some of these young characters (including Henery Hawk) even belonged to a different species and so in this sense Foghorn was not the “real” or biological father, but rather a “stepfather”.

Also, wasn’t the stepfather rather stupid always whistling a song that had become his trademark, even immediately after murdering someone? In this film, the old man would have recognized him immediately if he was not blind, and in any case he got into trouble by teaching his boy the song. But even in Stepfather III, he still whistled the same song everywhere. That seemed incredibly stupid since his greatest concern was obviously to avoid being noticed – not to say recognized – by people after committing a crime.