system
A chat on subreddit /r/NoStupidQuestions
human
i think it has to do with systemic poverty in populations, maybe.  
I'm from eastern ky and my family are all very... cautious about food. like very concerned about spoilage, i guess. they also all cook the shit out of all the meats.  
my assumption has been that once the coal industry stripped their land and put us all on company store diets (another story) the quality of food became more suspect.  
it would only take a few generations working with meat that had the potential to make you violently ill to change the culinary understanding of how food needs to be cooked, which will also ultimately change taste preferences.
gpt
I had an NJ Italian roommate in college.  He only used cold water to wash dishes because his grandma told him that's best.  I wondered why something so nonsensical would be practiced and perpetuated.  Maybe if you are a poor Italian immigrant living in an old NJ apartment building, you tell the kids to wash dishes with cold water so they don't use up all the hot water.  Hot water produced in some unreliable rusty boiler in the basement.  Old customs may start in poverty and are handed down even when circumstances change.