I never thought much about the possibility of political or cultural subliminal messages, if any, in shows like Andy Griffith, Green Acres or Petticoat Junction.
But I absolutely hated with a vengeance MASH, Hogan's Heroes and Gomer Pyle.
Not only for the obvious trivializing of war, POW camps, and the military in general.
But, as you suggest, I feel the effect, intentional or not, was to mainstream ideas like cross dressing, insubordination, fraternizing with the enemy, etc.
Not to mention the occasional themes that our enemies (NAZIs and Commies) weren't always so bad and that at times the US military wasn't much better.
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I think anything scene in the older shows is just trying to read something into it. Something that wasn’t meant to be subliminal.
I’m really surprised that the actors playing Sergeant Schultz and LeBeau roles . Both of those were in concentration camps and lost most of their family. Although the show was a POW camp, it’s still had to bring back nightmares. I would think. Plus Trivializing the experiences they went through.